Technical Requirements for Household Shelters

A household shelter (HS) is designed and constructed for the protection of people against weapon effects during a National Emergency. It should not be used for protection during other emergency situations such as a fire in a building. For quick access, HS is located inside the individual house or flat.

HS shall be incorporated as part of the house or flat. This can be achieved by efficient space planning as well as optimal integration of the HS location with other spaces in a house or flat.

The Technical Requirements for HS are applicable to all houses or flats, which are intended as complete and separate units for purpose of private dwelling.

Every HS shall be designed to a specific peacetime use. The other statutory requirements governing the design and use of the HS space shall also be complied with.

The configuration of a HS or NS on plan shall be rectangular, square, trapezoidal or L- shaped.

1. The maximum internal length of any floor and roof slab of a HS shall be 4000mm. The minimum internal width of a HS shall be 1200mm. The internal length and width of HS walls shall be designed with an increment of 50mm. See FIGURE 2.2.1(a).

2. If the configuration of HS on plan is rectangular or square, the minimum internal floor area and minimum internal volume of a HS shall be in accordance with TABLE 2.2.1(b).

3. If the configuration of HS on plan is trapezoidal or L-shaped, the minimum internal floor area, minimum internal volume of a HS and the number of 0.6 m x 0.6 m square units shall be as specified in TABLE 2.2.1(c) and as illustrated in FIGURE 2.2.1(a).

4. The maximum internal floor area of a HS shall be 4.8m2. Internal floor area exceeding 4.8m2 may be allowed subject to the approval from the relevant authority.

1. The minimum and maximum HS clear height shall be 2400 mm and 3900 mm respectively. See FIGURE 2.2.2(a).

2. The maximum NS clear height shall be 3900 mm. Where NS clear height is more than 3900 mm, intermediate RC slab or RC beams shall be provided. The RC beams shall be designed with at least equivalent stiffness to RC slab. If the NS is designed with 2 walls, RC beams shall be provided at the peripheral of NS. See FIGURE 2.2.2(b).

1. The minimum HS and NS wall thickness shall be in accordance with TABLE 2.3.1(a) for landed development and TABLE 2.3.1(b) for non-landed development.

2. Wall thickness of any HS or NS within the HS tower shall not be less than the wall thickness of the HS or NS above it.

3. The minimum thickness of the internal common wall between two adjacent HS for non-landed and landed cluster housing developments shall be 200mm thick. See FIGURE 2.3.1(c).

4. For landed developments where the two HS are abutting each other, the common wall shall be cast as two separate adjoining walls. See FIGURE 2.3.1(d).

5. The minimum thickness of the basement HS wall facing a reinforced concrete basement storey wall without any opening within the influence zone shall be 200mm. See FIGURE 2.4.6(a) and (b).

6. The minimum thickness of the basement HS wall which is in direct contact with earth throughout its entire height shall be in accordance with FIGURE 2.4.6(c).

7. The minimum thickness of the basement HS wall facing a reinforced concrete basement storey wall with opening within the influence zone shall be in accordance with TABLE 2.3.1(a).

1. Ceiling slab of top-most HS in non-landed development - 300mm. See FIGURE 2.3.2.

2. Slab between 2 HS - 175mm. See FIGURE 2.3.2.

3. Floor slab of bottom-most HS without NS below – 200mm. See FIGURE 2.3.2.

4. Floor slab of bottom-most NS in contact with soil – 200mm.

5. Slab between 2 enclosed NS – 175mm. See FIGURE 2.3.2.

6. Slab between HS and enclosed NS – 175mm. See FIGURE 2.3.2.

7. Ceiling slab of top-most HS in landed development – 300mm or 250mm (if there is a RC roof or another RC slab above the HS that is equal or extend beyond the required setback distance of that HS wall). See FIGURE 2.3.2(f).

1. Floor slab of HS that is directly supported by non-enclosed NS, NS walls or columns – 300mm. See FIGURE 2.3.2.

2. Ceiling slab of HS which is below non-enclosed NS, NS walls or columns – 300mm. See FIGURE 2.3.2.

3. Slab between 2 non-enclosed NS – 175 mm. See FIGURE 2.3.2.

1. A HS has to be positioned such that the setback distance of each HS wall shall be as large as practical and shall not be less than the minimum specified setback distance.

2. A HS with minimum 300mm thick ceiling slab in a landed house may have one of its walls (without HS door) abutting or near to an air well. The air well, has to be located such that it abuts a party wall and/or is surrounded by habitable space at ceiling slab level of the HS. The air well edge line shall not be regarded as EBL for the purpose of determining the minimum setback distance. The area of the air-well shall not be larger than 4.2m2 and the longer side of the air-well shall not be larger than 2.8m. See FIGURE 2.4.1(b).

3. Where a staircase in a landed house is located within setback distance of the HS wall (without HS door), such staircase can be built of either reinforced concrete or metal/steel or timber materials provided that it is covered with either reinforced concrete roof or clay tile roof. See FIGURE 2.4.1c(i) & c(ii).

4. Where non-reinforced concrete roof or non-clay tile roof is provided for landed house, there shall be reinforced concrete elements to meet setback distance at least one storey above the HS as stipulated in clauses 2.4.3 and 2.4.4. See FIGURE 2.4.1(d).

5. Where a non-reinforced concrete lift core in a landed house is located within setback distance of the HS wall (without HS door), such lift core shall be covered with either reinforced concrete roof or clay tile roof and meet the setback distance. See FIGURE 2.4.1e(i) & e(ii).

6. A HS can also be located in the basement of a landed house. Where the HS is located underground away from basement of landed house, an underground access route leading to HS must be provided with a reinforced concrete ceiling slab of minimum thickness of 125mm.

1. In a building of more than one-storey, the HS (or NS, if any) on every storey shall be located one on top of the other to form a vertical tower with its walls (where applicable) continuing to the foundation. See FIGURE 2.4.2(a).

2. Larger HS below the main roof level is allowed in the HS tower provided that:

   1. The number of the larger HS shall not be more than one third of the total number of storeys of a building or capped at 5 larger HS, whichever is lesser; and

   2. Only one wall of the larger HS is allowed to be relocated and discontinuous from the wall of the lower HS below it. See FIGURE 2.4.2(b).

3. The space within a NS is not intended for protection of occupants during a National Emergency.

1. The HS walls shall be located at minimum setback distances from the EBL. See FIGURE 2.4.3a(i) & a(ii). The setback distances of the HS wall with HS door and the remaining 3 HS walls shall comply with TABLE 2.4.3(a).

2. Where the storey height of a HS on the first storey is up to 3.6 m and is greater than the storey heights of the HS directly above it, the minimum setback distances of the HS on the first storey shall be at least the same as the setback distances of the HS above it.

3. Trellis constructed of RC or steel hollow section may be used to make up for the shortfall in setback distance for HS walls (without HS door). However, a minimum 1000mm RC ceiling slab measured from the HS wall shall be provided. A perpendicular or parallel trellis arrangement, or a combination of both, with respect to the HS wall concerned, shall comply with the geometrical configuration as shown in FIGURE 2.4.3c(i) & c(ii).

1. Where a down-hang beam is provided along the EBL in front of HS walls, the minimum setback distance of that HS wall can be reduced based on the effective storey height and in accordance with TABLE 2.4.4(a). The effective storey height is determined by the storey height less the depth ‘d’ of the down-hang beam. See FIGURE 2.4.4(a). If a down-hang beam is also provided along the EBL in front of the HS wall with HS door, the setback distance of this wall shall be in accordance with TABLE 2.4.4(a).

2. Trellis constructed of RC or steel hollow section may be used to make up for the shortfall in setback distance for HS walls (without HS door). However, a minimum 1000mm RC ceiling slab measured from the HS wall shall be provided as shown in FIGURE 2.4.4(b). A perpendicular or parallel trellis arrangement, or a combination of both, with respect to the HS wall concerned, shall comply with the geometrical configuration as shown in FIGURE 2.4.3(c).

3. Where the storey height of a HS on the first storey is up to 3.6 m and is greater than the storey heights of the HS directly above it, the minimum setback distances of the HS on the first storey shall be at least the same as the setback distances of the HS above it. Where a down-hang beam is provided at 2nd storey ceiling slab, the same down-hang beam shall be provided at 1st storey ceiling slab.

4. Clause 2.4.4 shall apply only if the width of the reinforced concrete down-hang beam is at least 125 mm.

1. Where HS is located close to exterior face of buildings or along external building line and there is a shortfall in the setback distance, it can be shielded by full height shielding walls with air gap in place of the required ceiling slab within the setback distance envelop. The full height shielding walls for such HS at different locations are shown in Figure 2.4.5(a) to (h) and as specified:

   1. Shielding wall “A” and “B” for HS with shortfall of setback distance on one side of HS (Type 1A, 1B & 1C). See Figure 2.4.5(a) to (c).

   2. Shielding wall “A” and “B” for HS with shortfall of setback distance on two sides of HS (Type 2A & 2B). See Figure 2.4.5(d) & (e).

   3. Shielding wall “C” and “D” for HS with shortfall of setback distance at one corner of HS. (Type 3A). See Figure 2.4.5(f).

   4. Shielding wall “C” and “E” for HS with shortfall of setback distance at one corner of HS. (Type 3B). See Figure 2.4.5(g).

   5. Shielding wall “A” and “B” that spans across two HS with shortfall of setback distance on one side of HS (Type 4). For such design, the HS wall with blast door shall be located opposite the shielding wall. See Figure 2.4.5 (h).

2. The materials and dimensions of the shielding walls “A” to “E” shall comply with the following:

   1. Shielding wall “A” covering the entire length of the HS wall, shall have an extension of minimum 300mm as shown in the Figure 2.4.5(a) to (e) and (h). The thickness and air gap for this shielding wall shall be:

      • minimum 150mm thick precast reinforced concrete wall with an air gap of 175mm to 225mm, or

      • minimum 200mm thick brick or solid block wall with an air gap of 175mm to 225mm.

      The shielding wall shall be cover at roof level with RC slab of at least 300mm thick. A RC slab of at least 125mm thick shall be provided within the air gap at the top-most storey level immediately below the roof slab.

   2. Shielding wall “B”, “C”, and “D” shall be minimum 100mm thick precast reinforced concrete wall or 200mm thick brick or solid block wall. This shielding wall shall be continuous and covers the entire setback distance along shielding wall.

   3. Shielding Wall “E” can be built of either RC or steel trellis. For RC trellis, the minimum member size is 125mm by 125mm. For steel trellis, the minimum steel hollow section size shall be 125mm by 125mm by 6mm thick (steel thickness). This shielding wall shall be continuous and cover the entire setback distance along the HS wall.

1. For the HS in the basement, the minimum setback distances of the HS wall with HS door and the remaining 3 HS walls shall comply with the TABLE 2.4.6(a). See FIGURE 2.4.6(a).

2. There is no setback distance requirement for basement HS wall with door if it faces a reinforced concrete basement wall not in direct contact with earth and the distance between them is at least 1500mm (with no openings within the influence zone). See FIGURE 2.4.6(b).

3. There is no setback distance requirement for basement HS wall (without HS door) of landed house. See FIGURE 2.4.6(c) if the HS wall is:

   1. 200mm thick and earth backing of up to HS roof level is of minimum distance 1000mm measured from the external face of the HS wall; or

   2. 250mm thick and earth backing of up to HS roof level is of minimum distance 300mm measured from HS wall. The scupper drain (if any) is allowed to be located minimum 300mm away from the HS wall; or

   3. 200mm thick and facing a reinforced concrete basement wall which is in direct contact with earth backing up to a minimum distance of 300mm throughout its full height.

   4. 200mm thick and facing a reinforced concrete basement storey wall not in direct contact with earth and the distance between them is at least 800mm (with no openings within the influence zone).

1. RC lift core can be located within the setback distances of HS walls. Where the RC lift core shares a common wall with the HS, an additional 50mm thickness (on top of the required HS wall thickness under table 2.3.1(a)) shall be provided to the common wall between lift wall and HS wall as shown in FIGURE 2.4.7(a).

2. Where the refuse chute is abutting the HS or located within the setback distances and it protrudes above the main roof, they shall comply with the requirements shown in FIGURE 2.4.7b(i) and b(ii).

3. Where the service riser is abutting the HS or located within the setback distances and it protrudes above the main roof, it shall comply with the requirements shown in FIGURE 2.4.7c(i) to c(vi). 8

4. Where the service riser is located within the setback distance of the HS walls (without door), the design shall comply with the requirements as shown in FIGURE 2.4.7d(i) & d(ii).

Void located within the setback distance of HS walls (without HS door) shall comply with the following requirements. See FIGURE 2.4.8(a).

1. Void located within 1000mm from HS walls:

   1. The void shall be enclosed by minimum thickness of full height 150mm thick RC walls or full height 200mm thick block/ brick walls.

   2. The maximum length and area of each void shall be 1000mm and 0.7m2 respectively. Such length and area of void shall be measured between the internal face of the walls.

   3. There shall be at least a full height 150mm thick RC wall or full height thick 200mm block/ brick wall between adjoining voids.

   4. RC slab of at least 300mm thick shall be provided at the roof.

   5. RC slab of at least 125mm thick shall be provided to cover the void at the top-most storey level immediately below the roof slab.

2. Void located beyond 1000mm from HS walls:

   1. The void shall be enclosed by minimum thickness of full height 150mm thick RC walls or full height 200mm thick block/ brick walls.

   2. The maximum length and area of each void shall be 1000mm and 0.7m2 respectively. Such length and area of void shall be measured between the internal face of the walls.

   3. There shall be at least a full height 150mm thick RC wall or full height thick 200mm block/ brick wall between adjoining voids.

   4. RC slab of at least 125mm thick shall be provided at the roof.

3. For void located behind a shielding wall, it shall be enclosed by minimum thickness of full height 150mm thick RC walls or full height 200mm thick block/ brick walls. See FIGURE 2.4.8 (c).

Staircase can be located within the setback distance of HS walls (without HS door) and shall comply with all the following requirements. See FIGURE 2.4.9.

1. Setback of the affected HS wall(s) shall comply with the relevant setback distances.

2. Clear height from FFL to soffit of ceiling or down-hang beam shall be maximum of 2800mm.

3. Distance from the EBL to edge of staircase landing shall be minimally 1300mm.

1. The opening dimensions of HS door shall be 700mm (W) x 1900mm (H). See FIGURE 2.5.1(a).

2. HS door frame that is cast together with the HS wall shall have single or double door rebate. See FIGURE 2.5.1(a) and (b).

1. There shall be a minimum 150mm reinforced concrete nib next to vertical edge of the HS door frame. See FIGURE 2.5.2(a).

2. For pre-cast door frame panel of Type 1, the reinforced concrete next to two vertical edges of the HS door frame shall be 300mm each. See FIGURE 3.5.5(a).

3. For pre-cast door frame panel of Type 2, the reinforced concrete next to vertical edges of the HS door frame shall be 300mm on one side, and 150mm plus the HS wall thickness on the other side. See FIGURE 3.5.5(f).

4. For pre-cast door frame panel of Type 3, the reinforced concrete panel with full length or width of HS wall must be properly connected to the in-situ HS walls and slabs. See FIGURE 3.5.5(k).

5. The door frame must be positioned such that its door is above FFL and can be opened at least 90°. See FIGURE 2.5.2(e).

The minimum thickness of the reinforced concrete ceiling slab immediately outside the HS wall with HS door shall be 125mm and structurally connected to HS tower. See FIGURE 2.5.3. This requirement shall only apply to HS in non-landed houses.

Precast hollow core household shelter shall be designed as a complete HS. For two adjoining HS, they can be formed by a complete HS and a C-shaped HS.

The various designs of precast hollow core HS are as follows:

1. Precast HS with HS door on longer wall and one of the ventilation sleeves above the door. See FIGURE 2.6.1(a).

2. Precast HS and C-shaped Precast HS connected at the shorter wall and with HS door on longer walls. See FIGURE 2.6.1(b).

3. Precast HS and C-shaped Precast HS connected at the longer wall and with HS door on longer walls. See FIGURE 2.6.1(c).

4. Precast HS and C-shaped Precast HS with connection between longer and shorter walls respectively and with HS doors on long wall. See FIGURE 2.6.1(d).

5. Precast HS adjoining cast in-situ walls/ columns. See FIGURE 2.6.1(e).

1. The internal length (L) and width (w) of the HS Walls shall be modular in size with an increment of 50mm.

2. Precast HS showing the arrangement of hollow cores in HS wall with its dimension as shown in FIGURE 3.5.6.1(a) to (h) and spacing, wall thickness, blast door, ventilation sleeves and electrical services shall be designed with dimensions as shown in Tables 3.5.6(a), 3.5.6(b) and 3.5.6(c).

3. Hollow cores shall be modular in size with an increment of 100mm for its length and 25mm for its width. See FIGURE 2.6.2(c).

4. The spacing between two adjacent hollow cores in HS wall shall be 100mm.

5. There shall be a minimum 150mm reinforced concrete nib next to vertical edge of the HS door frame.

6. Shear key of 35mm high shall be provided on wall above the HS door. See FIGURE 2.6.2(f).

1. The following electrical and communication fixtures in steel or PVC conduit system shall be provided inside the HS to provide basic stay-in and communication facilities:

   1. 13A switched socket outlets.

   2. Switch and lighting points.

   3. Communication line for telephony outlet.

2. The electrical and communication fixtures shall be designed and installed in accordance with the relevant local Codes of Practice for Info-communication Facilities in Building (COPIF) and other statutory requirements for peacetime usage.

3. The mounting height of the lighting switch and other electrical and communication fixtures shall comply with the requirement as stipulated in the other statutory codes and requirements for peacetime usage. See FIGURE 2.7.1(c).

4. Other fixtures, such as cabinets and shelves, which are required for peacetime use, are allowed provided they are easily dismantled and removed.

One 13A switched socket outlet shall be provided in the vicinity of adjacent to the telephony outlet. An additional 13A switched socket outlet shall be provided for other electrical appliances such as fan.

Light fittings shall be mounted on the soffit of HS ceiling slab using screws with non- metallic inserts. Wall-mounted light fittings are not permitted.

All cable entry openings to the HS shall be fully and properly sealed to ensure air-tightness as required under Clause 3.6.

1. Several NS can be stacked one on top of the other within an HS tower, without the need for NS floor slab to be connected to external floor slab, provided that the aggregate wall height of the NS does not exceed 12m. See FIGURE 2.8.1(a).

2. Aggregate wall height of NS refers to the sum of the height(s) of NS between two levels of the HS tower where the full external perimeters of the HS tower at those levels are structurally connected by floor slabs or tie beams to the structural frame of the building. The tie beams shall be designed with at least equivalent stiffness to the floor slab.

3. The minimum thickness of the intermediate slabs between 2 NS shall be 175mm.

The relevant architectural technical requirements of the shielded and unshielded NS Columns/ Walls as stipulated in Clause 3.3 shall be complied with.

If the loads from walls of HS towers cannot be carried directly to the foundation, transfer structure can be used to carry the loads indirectly to the foundation. The transfer structure could take the form of slab, beams, or combination of both. When transfer structure is provided to carry HS tower, additional technical requirements described herein shall be complied with. Please note the following conditions in the HS tower design supported by transfer structure:

1. RC slab shall be used as the shielding element of the transfer structure and its supporting columns and walls. See FIGURE 2.9.1(a) and (b).

2. The use of trellis or/and the adjacent building structure as shielding element of the transfer structure and its supporting columns and walls of HS is not allowed.

3. Only one transfer of HS loads in each tower by the transfer structure to its supporting columns and/ or walls is allowed. Multiple transfers of HS loads from the same HS tower are not allowed.

4. For unshielded exterior columns, the minimum size (either its diameter or the shorter dimension) shall be 500mm.

5. The use of pre-stressed concrete for the transfer structure and its supporting columns and walls is not permitted.

Additional design checks on transfer structure supporting HS tower is required. See Clause 3.3.

If a HS is located beneath an internal staircase, the following requirements shall apply. See Figure 2.10.

1. For the purpose of determining the minimum internal floor area of the HS in accordance with TABLE 2.2.1 (b) and TABLE 2.2.1 (c), only the portion of the space with clear height of at least 1500mm shall be taken into account.

2. For the purpose of determining the minimum internal volume of the HS in accordance with TABLE 2.2.1 (b) and TABLE 2.2.1 (c), the entire enclosed space may be used.

3. The minimum thickness of the HS ceiling slab and waist of the staircase shall be 300mm.

4. The minimum unobstructed distance from the HS wall with ventilation sleeve opening to the nearest face of any other internal structural element shall be at least 700mm. This is to facilitate the installation of a gas filtration unit when required during a National Emergency.

Finishes within a HS shall comply with the following:

1. The walls and the ceiling slab shall be cast with a smooth concrete finish.

2. The walls and ceiling slab may be finished with a skim coat of not thicker than 2mm.

3. No plastering or tiling shall be permitted on the walls and ceiling slab.

4. Floor tiles or floor finishes, which are laid on wet cement mortar, are permitted.

5. Skirting tiles laid on wet cement mortar are permitted up to a maximum 100mm high above the FFL.

Where there is only one exit staircase or exit scissors-staircase serving the non-landed houses, the minimum waist of exit staircase and the thickness of the intermediate landing slab shall be 150mm. The staircase shall be constructed of reinforced concrete.

A door recess on HS wall to accommodate the protrusion of the HS door handle when the HS door is fully open is allowed provided that (See FIGURE 2.13):

1. The dimensions are not larger than 160mm (length) x 80mm (height) x 40mm (depth) for HS wall of minimum 250mm thickness.

2. The spacing between the HS door handle recess and the external/ or internal socket points shall be at least 300mm apart.

* The GFA refers to GFA of the house which shall be in accordance with URA guidelines and other statutory requirements for peacetime usage.

*Effective Storey Height = Storey Height – Depth ‘d’ of Down-hang Beam. Refer to Figure 2.4.4(a).

The structural design of the HS tower shall take into account both the vertical and lateral loads, where applicable.

The HS tower shall be designed for maximum degrees of redundancy in the structural system against weapon effects.

1. The minimum concrete strength class shall be grade C25/30 for landed residential developments and C32/40 for non-landed residential developments. Concrete used in HS/NS structures (including hollow core and joints), as well as concrete used for structures within shelter setback distance, should be of normal concrete density (2400kg/m3) and consists of 20mm nominal maximum size coarse aggregate.

2. The use of pre-stressed concrete for the HS tower, and the transfer structure and its supporting walls and columns is not permitted.

The steel reinforcement of concrete shall be welded steel fabric mesh and hot rolled steel bars. The minimum yield strength for the main reinforcements and shear links in the structural elements forming the HS or NS shall be 500 N/mm2, and of ductility class B or better.

The vertically continuity of HS and NS walls, where applicable, to the foundation shall comply with clause 2.4.2.

The beam that is supported by HS wall shall be designed and detailed as simply supported on the HS wall or cantilever from the HS wall.

No additional design checks on HS tower is required if its supporting NS elements, wall(s), column(s) or any of its combination, are shielded. These structural elements are deemed adequately shielded if reinforced concrete slab or other equivalent structural forms provided above them is extended beyond their edges by a minimum length of 0.5H, where H is the aggregate wall height of NS. See FIGURE 3.3.3.

The following requirements are to be complied with if the design adopts:

1. Unshielded NS Wall(s)

   The minimum thickness of each NS wall shall be 300mm. The HS tower shall be designed against the most severe effects as the result of the removal of a portion of the NS wall equivalent to an opening of 1500mm diameter on the NS wall at its most critical location. See FIGURE 3.3.4(a).

2. Unshielded NS Column(s)

   The minimum size (either its diameter or the shorter dimension) of NS column shall be 500mm. The HS tower shall be designed against the most severe effects as the result of the removal of any one NS column. See FIGURE 3.3.4(b).

3. Combination of Unshielded NS Wall(s) and NS Column(s)

   The minimum thickness of each NS wall and minimum size (either its diameter or the shorter dimension) of NS column shall be 300mm and 500mm respectively. The HS tower shall be designed against the most severe effects as the result of the following (See FIGURE 3.3.4(c)):

   1. Removal of a portion of the NS wall equivalent to an opening of 1500mm diameter on the NS wall at its most critical location and

   2. Removal of any one NS column at a time.

   The above removal of wall or column shall be considered one at a time.

4. The following criteria are to be used when performing design checks for Clause 3.3.4(a), 3.3.4(b) or 3.3.4(c):

   1. The design loads shall be based on the load combination and values of partial safety factors for actions (ɣ_f) in accordance with Table 3.3.4(d).

   2. The design strength for a given material is derived from the characteristic strength divided by the partial safety factor for strength of material (m), which shall be 1.2 for concrete and 1.0 for reinforcement.

The design loads for the transfer structure shall include a collapse load of 20kN/m2 acting on transfer slab/beam. An additional load combination in the design of transfer structure supporting the HS tower, incorporating the collapse load, shall be considered with partial safety factors for actions (f) given in Table 3.3.5.1. Only one transfer of HS loads from each tower by the transfer structure to its supporting columns and/ or walls is allowed. Multiple transfers of HS load from the same HS tower is not allowed. See FIGURE 2.9.1(a) and FIGURE 2.9.1(b).

No additional design checks on transfer structure are required, besides the requirement in Clause 3.3.5.1, if the transfer structures are shielded by RC slab or other equivalent structural forms. The transfer structure is deemed adequately shielded if Clause 3.3.5.2(a) and 3.3.5.2(b) are complied with:

1. Shielding of Transfer slab/beams

   The transfer slab/beams are deemed to be shielded if RC shielding slab or other equivalent structural forms is provided directly above the transfer slab/beams and is extended beyond their external edges by a minimum length of 0.5H1, where H1 is the vertical distance between the top level of the RC shielding slab and the soffit of transfer slab/beams. See FIGURE 3.3.5.2(a).

2. Shielding of Exterior Columns

   The transfer columns are deemed to be shielded if RC shielding slab or other equivalent structural forms is provided above the exterior columns and is extended beyond their exterior edges by a minimum length of 0.5H2 or 0.5H3, where H2 and H3 are the vertical distances between the top level of the RC shielding slab and the base of the exterior columns. See FIGURE 3.3.5.2(a).

Besides the requirement in Clause 3.3.5.1, additional design checks on unshielded transfer structure (See FIGURE 3.3.5.3) shall be carried out in accordance with the following requirements:

1. Unshielded Transfer Slab/Beams

   The transfer structure shall be designed against the most severe effects as the result of the removal of a portion of the transfer slab/beam equivalent to an opening of 1500mm diameter on the transfer slab/beams at its most critical location. See FIGURE 3.3.5.3a (i) and FIGURE 3.3.5.3a (ii).

2. Unshielded Exterior Columns and Walls

   The minimum size (either its diameter or shorter dimension) of the exterior columns shall be 500mm and the minimum thickness of the wall shall be 300mm. The transfer structure shall be designed against the most severe effects as the result of the removal of any one exterior column at a time or the removal of a portion of the exterior wall equivalent to an opening of 1500mm diameter on the transfer wall at its most critical location. Alternative path for load transfer shall be designed for such cases. See FIGURE 3.3.5.3b (i) and FIGURE 3.3.5.3b (ii).

3. The following are the criteria to be used when performing design checks for Clause 3.3.5.3(a) and 3.3.5.3(b):

   1. The design loads including collapse load, shall be based on the load combination and values of partial safety factors for loads (f) in accordance with Table 3.3.5.1.

   2. The design strength for a given material is derived from the characteristic strength divided by the partial safety factor for strength of material (m), which shall be 1.2 for concrete and 1.0 for reinforcement.

The minimum member size of HS and NS shall be as stipulated in Chapter 2 – Architectural Design.

All diameters of reinforcement specified hereinafter shall refer to minimum bar diameters. All spacing of reinforcement specified hereinafter shall refer to maximum spacing of reinforcement in both directions.

1. Minimum Reinforcement in HS walls in landed development – refer to TABLE 3.4.2.1(a).

2. Minimum Reinforcement in HS or NS walls in non-landed development – refer to TABLE 3.4.2.1(b).

3. Reinforcements at both faces of the internal common wall shall be H 10-100 c/c in both directions. The shear links shall be H8-600 c/c in both directions.

4. Reinforcements at each sides of the blast door frame and its stiffeners shall be 2 H13.

Top and bottom reinforcements of the slab shall be H 10-100 c/c in both directions. The shear links shall be H8-600 c/c in both directions.

1. The ceiling slab immediately outside the HS wall with HS door shall be constructed of reinforced concrete. Two layers of reinforcement bars (top and bottom) of H 10-100 c/c in both directions shall be provided for the ceiling slab with minimum 125mm thick.

2. The reinforcements of every floor slab immediately outside HS tower walls shall be structurally connected to HS tower.

For HS slab integrated with the pile-cap or footing of more than 500mm thick, shear links is not required. The maximum spacing of main reinforcement shall be 200mm c/c.

The shielding wall for the HS wall could be built of brick/ block wall and precast reinforced concrete wall. See FIGURE 2.4.5(a) to (h).

1. The brick/ block wall shall be tied to the reinforced concrete walls or columns by a wall tie system to ensure lateral stability.

2. The precast reinforced concrete wall shall comply with the following requirements:

   1. The steel welded mesh of minimum H10 spaced at 200mm vertically and horizontally shall be used for both faces of shielding precast reinforced concrete wall.

   2. Reinforcements at both faces of the shielding wall shall be minimum H10 200 c/c. Minimum links shall be provided in both directions.

The HS tower is to be detailed to allow for the installation of services and fixtures in HS and to resist spalling of the internal face of HS walls, soffit of ceiling slabs and/or finishes on HS floor slab.

Requirements for lap and anchorage length of reinforcement bars are as follows:

1. Full lap and anchorage length of reinforcements in HS and NS walls and slabs shall be provided. The lap length shall take into account good or poor bond condition, steel bar diameter, shape of steel bar, concrete cover, steel strength and location where reinforcement bar laps and confinement of transverse bars.

2. Minimum tension lap and anchorage length of reinforcement bars for concrete grades C25/30 and C32/40 with good bond condition shall be as shown in TABLE 3.5.2(a) and TABLE 3.5.2(b) respectively. Longer tension lap and anchorage length shall be provided if they are required to meet poor bond condition and/or the structural load and safety requirements.

3. Welding of reinforcement bars to attain tension anchorage length or tension lapped length is not permitted.

4. Bundled bars are not permitted.

The minimum and maximum concrete covers to the main reinforcement shall be 25mm and 40mm respectively.

Cast-In-Situ HS elements shall comply with the dimensions and detailed requirements as shown in the following figures:

• FIGURE 3.5.4 (a) - Plan of HS

• FIGURE 3.5.4 (b) - Sectional details of HS slabs/walls

• FIGURE 3.5.4 (c) - Sectional details of HS slabs/walls

• FIGURE 3.5.4 (d) - Plan of two HS with an internal common wall

• FIGURE 3.5.4 (e) - Sectional details of two HS with an internal common wall

• FIGURE 3.5.4 (f) - Details of HS wall reinforcement bar near HS door

• FIGURE 3.5.4 (g) - Typical details of embedded conduit in HS wall

• FIGURE 3.5.4 (h) - Typical details of trimmer bars for ventilation sleeve

• FIGURE 3.5.4 (i) - Typical details of trimmer bars for wall recess

• FIGURE 3.5.4 (j) - Details of shear links in HS slabs/walls

• FIGURE 3.5.5 (a) - Plan of HS with pre-cast HS door frame panel (Type 1)

• FIGURE 3.5.5 (b) - Details and Sections of pre-cast HS door frame panel with ventilation sleeve above it (Type 1)

• FIGURE 3.5.5 (c) - Sections of pre-cast HS door frame panel with ventilation sleeve above it (Type 1)

• FIGURE 3.5.5 (d) - Details and Sections of pre-cast HS door frame panel with ventilation sleeve at its side (Type 1)

• FIGURE 3.5.5 (e) - Sections of pre-cast HS door frame panel with ventilation sleeve at its side (Type 1)

• FIGURE 3.5.5 (f) - Plan of HS with pre-cast HS door frame panel (Type 2)

• FIGURE 3.5.5 (g) - Details and sections of pre-cast HS door frame panel with ventilation sleeve above it (Type 2)

• FIGURE 3.5.5 (h) - Sections of pre-cast HS door frame panel with ventilation sleeve above it (Type 2)

• FIGURE 3.5.5 (i) - Details and sections of pre-cast HS door frame panel with ventilation sleeve at its side (Type 2)

• FIGURE 3.5.5 (j) - Sections of pre-cast HS door frame panel with ventilation at its side (Type 2)

• FIGURE 3.5.5 (k) - Plan of HS with pre-cast HS door frame panel (Type 3)

• FIGURE 3.5.5 (l) - Details of pre-cast HS door frame panel (Type 3)

• FIGURE 3.5.5 (m) - Sections of pre-cast HS door frame panel (Type 3)

• FIGURE 3.5.5 (n) - Sections of pre-cast HS door frame panel (Type 3)

• FIGURE 3.5.5 (o)(i) - Typical details and sections of reinforcements at ventilation sleeve location

• FIGURE 3.5.5 (o)(ii) - Typical details and sections of reinforcements at ventilation sleeve location

1. Precast HS Hollow Core shall comply with the dimensions, reinforcement bar and connection detail requirements as shown in the following tables and figures.

2. For precast HS walls abutting lift walls and requiring additional 50mm thickness, the hollow core sizes shall remain to be same (Table 3.5.6(b)) as the precast HS walls with normal thickness. The concrete cover thickening shall occur at the common wall between HS wall and lift wall.

• TABLE 3.5.6 (a) - Dimension of Precast Hollow Cores HS

• TABLE 3.5.6 (b) - HS wall thickness and Sizes of Hollow Cores

• TABLE 3.5.6 (c) - Minimum Reinforcement Bars in Hollow Cores

• TABLE 3.5.6 (d) - Minimum Thickness of Slab and Reinforced Concrete Topping

• FIGURE 3.5.6.1 (a) - Precast HS with HS door on longer wall and one of the ventilation sleeves above the door (Type 1)

• FIGURE 3.5.6.1 (b) - Precast HS with HS door on shorter wall and one of the ventilation sleeves above the door (Type 2)

• FIGURE 3.5.6.1 (c) - Precast HS showing ventilation sleeve and internal electrical fixtures on the same wall (Type 3)

• FIGURE 3.5.6.1 (d) - Precast HS and C-shaped Precast HS connected at the shorter wall and with HS door on longer walls (Type 4)

• FIGURE 3.5.6.1 (e) - Precast HS and C-shaped Precast HS connected at the longer wall and with HS door on longer walls (Type 5)

• FIGURE 3.5.6.1 (f) - Precast HS and C-shaped Precast HS connected at the longer wall and with HS door each on the longer wall and shorter wall (Type 5A)

• FIGURE 3.5.6.1 (g) - Precast HS and C-shaped Precast HS with connection between longer and shorter walls respectively and with HS doors on longer wall (Type 6)

• FIGURE 3.5.6.1(h) - Precast HS and C-shaped Precast HS with connection between longer and shorter walls respectively and with HS door each on longer wall and shorter wall (Type 6A)

• FIGURE 3.5.6.2 (a) - Reinforcement Bar Details of Wall, Rib and Blast Door on Long Wall of Precast HS

• FIGURE 3.5.6.2 (b) - Reinforcement Bar Details of Wall, Rib and Blast Door on Short Wall of Precast HS

• FIGURE 3.5.6.2 (c) - Plan and Section of Rib with Shear Links

• FIGURE 3.5.6.2 (d) - Reinforcement Bar Details of Wall and Rib for C-Shaped Precast HS

• FIGURE 3.5.6.2 (e) - Reinforcement Bar Details of Wall and Rib for C-Shaped Precast HS

• FIGURE 3.5.6.2 (f) - Connection Details Between Two Precast HS

• FIGURE 3.5.6.2 (g) - Connection Details Between Precast HS and Cast In-Situ Wall/ Column

• FIGURE 3.5.6.2 (h) - Reinforcement Bar Details at Concrete Rib

• FIGURE 3.5.6.2 (i) - Details of Reinforcement Bars near Door Frame and at Electrical Fixtures on Internal Face of Precast HS

• FIGURE 3.5.6.2 (j) - Details of Trimmer Bars for Ventilation Sleeve

• FIGURE 3.5.6.2 (k) - Details of Trimmer Bars for Wall Recess for HS Door Handle

• FIGURE 3.5.6.2 (l) - Precast HS Wall with Connection Details for Ventilation Sleeve and Electrical Services

• FIGURE 3.5.6.2 (m) - Precast HS Wall with Connection Details for Electrical Services

• FIGURE 3.5.6.2 (n) - Cage Reinforcement Bars in Hollow Cores

• FIGURE 3.5.6.2 (o) - Reinforcement Bars Lapping in Hollow Cores

• FIGURE 3.5.6.2 (p) - Hollow Cores Shape

• FIGURE 3.5.6.3 (a) - Isometric View of Precast HS with Bolts and Steel Plates Connection (Type 1 without Blocked-Out for Beam)

• FIGURE 3.5.6.3 (b) - Isometric View of Precast HS with Bolts and Steel Plates Connection (Type 2 without Blocked-Out for Beam)

• FIGURE 3.5.6.3 (c) - Splice Sleeve Connection Details Between Precast HS and Cast In-Situ Element and Bolt Connection Details Between Two Precast HS

• FIGURE 3.5.6.3 (d) - Splice Sleeve Connection Details for Precast HS Tower

• FIGURE 3.5.6.3 (e) - Connection Details Between lower and upper Precast HS (Detail A)

• FIGURE 3.5.6.3 (f)- Connection Details Between lower and upper Precast HS (Detail B)

• FIGURE 3.5.6.3 (g) - Connection Details Between lower and upper Precast HS (Detail C)

• FIGURE 3.5.6.3 (h) - Isometric View of Precast HS with Splice Sleeve Connection (Reinforcement Bars Details)

• FIGURE 3.5.6.3 (i) - Detail of Splice Sleeve Connection

• FIGURE 3.5.6.3 (j) - Details of Precast Plank (marked as PS) and Concrete Topping

• FIGURE 3.5.6.3 (k) - Electrical Fixtures on External Face of Precast HS

• FIGURE 3.5.6.3 (l) - Isometric View of Precast HS with Bolts and Steel Plates Connection (Type 3 with Blocked-Out for Beam)

• FIGURE 3.5.6.3 (m) - Isometric View of Precast HS with Bolts and Steel Plates Connection (Type 4 with Blocked-Out for Beam)

1. Construction joints in an HS tower shall be properly executed to ensure that the strength and the integrity of the HS are not impaired. The type and location of joints shall be specified in the design after taking into account the following:

   1. A concrete kicker, if provided, shall not be more than 100mm high.

   2. All HS walls located within each storey shall be cast in one operation.

2. Expansion joints or contraction joints in the HS tower are not permitted.

The load transfer of these PPVC modules shall not adversely affect the structural integrity and protection level of the HS in any way.

1. There shall not be load transfer from PPVC modules (transferring shear, bending moment, etc) onto HS wall unless the connection has been checked for structural adequacy and it is confirmed such load does not compromise the HS protective design.

2. There shall be no recess in HS wall that cause reduction in HS wall thickness due to PPVC connections.

1. All service conduits shall not penetrate through the walls and slabs of the HS. Service conduits for electrical service cables which are cast in the external face of HS can be embedded in the HS wall. Other than this, all service conduits which do not serve the HS shall not be embedded within the HS walls and slabs.

2. Two cast-in service outlets located directly back-to-back on the internal and external faces of the HS wall are not permitted as shown in FIGURE 3.6.1(b). Service outlets shall be fixed with at least a clear distance of 300mm between each other. See FIGURE 2.13.

3. Risers for services can be mounted on the external face of HS tower walls.

4. Where service cables and fixtures in the HS are exposed on internal walls, non- metallic inserts are to be used for their mounting. For embedded service cables and fixtures serving the HS, the details as shown in FIGURE 3.5.4(g) shall be followed. The encasement for the switch, 13A switched socket outlet and communication line for telephony outlets of Clause 2.7 shall be made of hot- dipped galvanised steel construction. See FIGURE 3.6.1(d).

5. A maximum of 4 numbers of 25mm diameter conduits are allowed to be embedded within the HS walls for electrical cables serving fixtures in the HS. Both ends of these conduits on the internal and the external of the HS shall be fully sealed with sealing material in accordance with the manufacturer’s specification and up to a depth of not less than 100mm into the conduits to ensure air-tightness of HS.

Service pipes for water or gas are allowed to penetrate through the HS walls provided that they are laid inside a stainless steel casing encased by 150mm reinforced concrete all round. See FIGURE 3.6.2. Joints in water pipe, gas pipe or the stainless steel conduit shall be located outside the HS.

Refuse chute and risers for water and gas services can be mounted on the external face of HS walls. Where this structure protrudes above the roof, it shall be designed with a minimum 300mm reinforced concrete all round and reinforcement details as shown in FIGURES 3.6.3(a) to (e).

*Dimensions with increment of 100mm

#Dimensions with increment of 50mm

^Dimensions with increment of 25mm

Notes: If larger size of reinforcement bars are required in the hollow cores, the number of such reinforcement bars shall remain the same as stipulated in the table above.

Two 125mm diameter ventilation sleeves shall be cast into the wall/s of each HS. Only ventilation sleeves of an approved design from an approved HS steelworks supplier shall be used.

The position of each ventilation sleeve shall comply with the following. See FIGURE 4.2(a) and (b).

1. The height of each opening of ventilation sleeve, measured from the centre of the opening to internal FFL of the HS shall be between 1900mm and 3600mm.

2. The ventilation sleeve shall be positioned such that there is sufficient clearance from any structural elements and services, and not to be located in areas such as toilets, bathroom. The centre of the ventilation sleeve to the soffit of ceiling and the nearest face of the internal HS walls shall be at least 300mm. In addition, there shall be a minimum unobstructed distance of at least 700mm from the face of the ventilation sleeve openings to the nearest face of any other internal structural elements within the HS. See Figure 2.10.

3. Where the ventilation sleeve is placed above or adjacent to the HS door frame, the centre of the ventilation sleeve shall be at least 250mm from the nearest edge of the door frame.

4. The shortest distance between the centres of the two ventilation sleeves shall be at least 1000mm.

The minimum clearance from the fragmentation plate to RC beam or structure or service shall be 50mm. Where the RC beam or structure or service is fronting the fragmentation plate of ventilation sleeve, the clear distance between them shall be at least 500mm. See FIGURE 4.3.1.

Where false ceilings are provided outside the HS and below the ventilation sleeves, there shall be perforated access panels of minimum size of 600mm x 600mm positioned directly below each ventilation sleeve. See FIGURE 4.3.2.

Each ventilation sleeve shall have a 6mm thick stainless steel fragmentation plate mounted on the external face using 8mm stainless steel bolts. See FIGURE 4.4(a) and (b).

The HS door shall provide an airtight closure to the HS and shall be designed to open outwards from the HS.

HS door frame that is cast together with the HS wall shall have single or double door rebate. See FIGURE 2.5.1(a) and FIGURE 2.5.1(b).

Only HS doors of an approved design from an approved HS steelworks supplier, and which have been certified and listed under the Product Listing Scheme shall be used.

Every HS door shall have a HS door notice affixed on its internal face. See FIGURE 5.3(a). A sample notice is shown in FIGURE 5.3(b).

1. Manner of Application : To be affixed on the internal HS door by pressure sensitive and strong adhesive.

2. Special Features : Non-brittle, rub and mar resistant, storage stability and colour fastness under

   light.

3. Text, Lettering, Layout : Conform to sample notice.

4. Colours : Background is light yellow, lettering is black, sub-headings, border and

   triangular logo area are red.

As the HS is designed to resist weapon effects, good workmanship is essential to achieve the designed protection level.

The following shall be observed:

1. Only the non-removable type of form-tie (form-tie without through opening) to secure formwork before casting of HS wall is permitted. Upon the removal of every recessible type of plastic cones from the form-tie, the recess shall be sealed with non-shrink grout. The use of reinforcement bar as form-tie is not permitted.

2. To avoid bending, warping or displacement of HS door frame and honeycombing due to inadequate compaction or leakage of cementitious grout, additional precaution to ensure adequate compaction shall be taken while casting the concrete near the HS door frame.

3. All embedded items shall be placed and tightly secured in their intended location to ensure their stability during casting. All hacking and drilling of HS tower walls, ceiling slabs or floor slabs are not permitted without prior approval.

4. The exposed surfaces of HS walls and soffit of HS ceiling slabs shall be cast with smooth concrete finish. A maximum of 2mm thick skim coat on the internal face of the HS walls and ceiling slabs of HS is allowed.

5. The concrete structural elements shall be adequately compacted to ensure air- tightness. Rectification to concrete areas with segregation or honeycombing shall not be carried out without prior approval.

6. Rectification to irregularities of exposed surfaces shall not be carried out without prior approval.

7. Method statement of the remedial work on structural elements, including HS door frame, shall be approved by the Commissioner of Building Control.

The following shall be observed:

1. Allowing an opening in the HS wall and later erecting the HS door frame and door leaf in this opening, followed by casting concrete around it is not permitted.

2. When casting the HS wall with HS door frame, a dummy door leaf of adequate design shall be placed to ensure the stability and prevent the bending, warping or displacement of the HS door frame during concreting.

3. The FFL of the floor slab outside the HS shall be done such that the HS door can be opened adequately for the peacetime use of the HS.

4. Modification of door frame, cutting of door frame stiffener for ease of installing is not permitted.

For ventilation purposes during peacetime, at least 25% of total area of the two ventilation openings shall be kept uncovered.

All electrical and communication fixtures such as switch and lighting point, switched socket outlets and communication line for telephony outlets, including HS door notice shall be provided inside the completed HS. The service conduits with electrical cables serving the HS shall be provided prior to commissioning.

A HS is considered commissioned only if the HS passes all the following tests in one inspection:

1. Light penetration test of HS door – an acceptable test method to check on light penetration into the HS is to use a torch-light from the exterior of HS door. The test is considered to have passed if no light could be seen from the inside of HS.

2. Chalk mark test on the HS door – an acceptable test method is to apply chalk to the part of the door frame where the door seal will come into contact with when the door is closed. The test is considered to have passed if there is an unbroken and uniform transfer of the chalk markings onto the door seal when the door is closed and re-opened.

3. Air-tightness test of the HS – an acceptable test method is to pressurise the HS and measure the rate of pressure drop or the pressure difference between the interior and exterior of the HS. The pressure gauge can be used for the test. The HS is pressurised by pumping air into the HS such that there is a pressure difference of 250 Pa between inside and outside of HS. The HS is considered to have passed the test if the pressure gauge shows more than or equal to 50 Pa after 45 seconds.

The ventilation sleeves of the HS, which have been closed for the commissioning tests, shall be opened after the tests to comply with Clause 6.4 for ventilation during peacetime.

*The pressure gauge used should have a valid calibration certificate and a dial size with a scale of 0 to 50mm or 0 to 500 Pa. (Note: 1mm = 10 Pa).

Any repair or alteration or renovation works, which are likely to weaken or damage any structural elements of the HS or NS, is not permitted.

1. Laying of floor tiles bonded to wet cement mortar. The total thickness of floor finishes and screed shall not exceed 50mm.

2. Laying of floor skirting tiles (up to a maximum of 100mm high) by bonding them with wet cement mortar to HS walls.

3. Laying of vinyl or linoleum flooring.

4. Applying splatter dash or equivalent to the external face of HS walls only to provide rough surface for feature wall panels or wall tiles installation.

5. Painting of walls, ceiling or door. In the case of HS door, owners shall not cover up or paint over the HS door notice (See Clause 5.3), locking bolts or door seal. The old paint coat on door and door frame is to be removed prior to repainting to avoid increase paint thickness resulting in difficulty in closing and opening of the door. The new paint coat must be dried up completely before closing the door as wet or damp paint will cause the door/ rubber gasket to stick onto the door frame when opening the door.

6. Painting on only the exterior face of the 6mm fragmentation stainless steel plate of the ventilation sleeves.

7. Drilling into internal face of HS walls and ceiling slabs to a depth of not more than 50mm to affix inserts and removable screws is allowed. Fixtures such as pictures, posters, cabinets or shelves on internal face of HS walls will have to be removed by the owners within 48 hours upon notification. There is no restriction to the diameter of the non-metallic insert as long as it does not exceed 50mm in length. It is the owner’s responsibility to ensure that the strength of the insert is adequately provided for the intended purpose.

8. Power driven nails are allowed only on external face of the HS walls to facilitate flexibility in mounting of features/ fixtures by owners.

9. Fragmentation plates (Clause 4.4) of the ventilation sleeves are allowed to be removed provided that the fragmentation plates and its bolts and nuts are mounted or kept together for use when needed. If the plate is to be mounted on the HS wall, it shall be done in accordance with Clause 7.2.1(g).

10. Closing or covering up of ventilation openings by removable aesthetic or architectural finishes is allowed, provided that at least 25% of the total area of the two openings shall be left uncovered for ventilation purposes during peacetime.

11. The minimum clearance from the fragmentation plate to RC beam or structure or service shall be 50mm. Where the RC beam or structure or service is fronting the fragmentation plate of ventilation sleeve, the clear distance between them shall be at least 500mm. See FIGURE 4.3.1.

12. Where false ceilings are provided outside the HS and below the ventilation sleeves, there shall be perforated access panels of minimum size of 600mm x 600mm positioned directly below each ventilation sleeve. See FIGURE 4.3.2.

1. Laying of wall tiles or spray of rock stone finish, cement sand finish and gypsum plastering on the internal faces of HS walls.

2. Laying of floor tiles using adhesive materials.

3. Laying of 2nd layer of tiles on floor or skirting tiles.

4. Installation of cornices within the HS.

5. Installation works with fixings using power driven nails into the internal HS walls.

6. Tampering with, removing or covering up of the HS door notice. The HS door notice provides important information to the occupants on the use of the HS.

7. Hacking and drilling of HS walls, floor slabs, and ceiling slabs other than drilling permitted in Clause 7.2.1(g) and 7.2.1(h).

8. Hacking to both internal and external face of the household shelter walls to form key for tiling.

9. Hacking on external face of HS wall for mounting of feature wall panels or wall tiles installation.

10. Modifying, changing, removing or tampering of HS door.

11. Modifying, altering or tampering with any part of the ventilation openings, plates and the mounting devices such as bolts and nuts.

12. Painting to the interior face of the 6mm fragmentation stainless steel plate of the ventilation sleeves, the ventilation sleeves, “O” ring rubber gaskets and the four or eight numbers of stainless-steel bolts which hold the steel plate to the sleeves.

Hacking and drilling of NS walls, columns, floor slabs and ceiling slabs.

1. This Chapter stipulates requirements relating to the certification of shelter products regulated by SCDF under the Product Listing Scheme. These requirements include the acceptable test standards, certification scheme and surveillance regime for the regulated shelter product (refer to Table 8.1).

2. For the full list of requirements, this Chapter shall be read in conjunction with the Civil Defence Shelter Act (CDSA) and CT 23 of SAC’s “Criteria for Product Certification Bodies (Regulated Shelter Products)”.

“Accredited certification body” (CB) refers to a body corporate or corporation incorporated or constituted under the law of Singapore, accredited under the Singapore Accreditation Council (SAC)’s certification body accreditation scheme administered by the Enterprise Singapore Board.

“Accredited laboratory” refers to a body corporate or corporation providing laboratory testing services, which is accredited under SAC’s laboratory accreditation scheme administered by the Enterprise Singapore Board or recognised under the International Laboratory Accreditation Cooperation (ILAC) Mutual Agreement/Arrangement between Singapore and other countries.

“Certificate of Conformity” refers to a certificate issued by CBs for a regulated shelter product that meets product testing standards and certification requirements. These certified products shall be recorded in a product directory on the CB’s website for reference and verification of the CoCs’ validity.

“Local representative” refers to the Singapore-registered agent/partner appointed by a foreign CoC holder, in order for its certified regulated shelter products to be supplied in Singapore.

“Mutual Recognition Arrangement” or “Mutual Recognition Agreement” refers to the arrangements signed between SAC and other international assessment bodies, which mutually recognise reports and certificates issued by an accredited Conformity Assessment Body (CAB) as equivalent to their own accreditation requirements.

“Product listing scheme” refers to the third-party certification scheme administered by SCDF for regulated shelter products.

“Scheme Type 5” consists of type testing and factory inspection during initial certification, and ongoing assessment of the entire quality management system, including auditing the production process and management system. Surveillance testing of the product is done either from the market or at the point of production, or both, to check that items produced fulfil the specified requirements.

“Serial label” refers to a certification label issued by CBs, with unique serial numbers. These are affixed to certified regulated shelter products, such as HS doors (refer to Table 8.1). Such labels allow tracing of these products to their corresponding CoC and the specific installation location of each product.

"Surveillance window”, also known as “surveillance cycle”, refers to the period of 12 or 36 months (as stipulated in Table 8.1), starting from the date that a CoC is issued in relation to a regulated shelter product, and every subsequent period of 12 or 36 months or shorter, if the CoC expires, or is terminated or withdrawn. Products may be subjected to post-certification testing and/or inspection, based on the surveillance window.

“Suspension of CoC” refers to the temporary invalidation of a CoC by a CB under circumstances not limited to the following:

1. Non-compliance to any component of the surveillance regime.

2. Products are suspected to not meet shelter requirements but are still in the process of being tested/investigated.

3. CoC holder breaching the CB’s terms and conditions (including non-payment of fees).

“Termination of CoC” refers to the cancellation of a CoC, either on the request of the CoC holder before its expiry, or due to reasons not related to shelter requirements. Examples of such circumstances include:

1. CoC holder ceases to supply the product due to business considerations (e.g. shutting down of business, liquidation).

2. CoC holder fails to take adequate rectification measures within the given timeframe, despite being suspended for a breach in the CB’s terms and conditions (including non-payment of fees).

“Type testing”, also known as prototype testing, refers to testing of a product according to the test standard(s) and specification(s) for that product for the application of CoC, as specified in Table 8.2.

“Withdrawal of CoC” refers to the cancellation of a CoC by the CB under circumstances not limited to the following:

1. Non-compliance with the requirements of the Product Listing Scheme, including:

   1. Regulated shelter product that is supplied to the industry differs from the prototype described in the CoC and laboratory test report.

   2. Misuse of certification mark, logo and certificates.

   3. Supply of products from a factory which differs from the factory declared during the CoC application.

2. Failure to take adequate rectification measures within the given timeframe, despite being suspended for a shelter-related non-compliance.

3. Non-compliance that indicates failure of production process to consistently produce products of acceptable quality, including:

   1. Failure or refusal of test/analysis of the product.'

   2. The surveillance regime is not completed within the surveillance window.

4. Other reasons related to shelter requirements.

All regulated shelter products shall be certified and have valid CoCs before they can be used on/in buildings as part of shelter works in Singapore (henceforth, for the purpose of this Chapter, “use in Singapore” shall be taken to mean “on/in buildings as part of shelter works in Singapore”).

Certification of regulated shelter products under the Product Listing Scheme shall be based on test report(s) that were issued within the specified timeframes, as listed below.\

1. A CoC for regulated shelter products is valid for 5 years from the date of issuance.

2. A CoC which is terminated, expired or withdrawn shall be considered permanently invalid, whereas a CoC which is suspended shall be considered temporarily invalid until the suspension is lifted.

3. The status of the CoC will determine whether the regulated shelter products are permitted to be supplied and used in Singapore. Information relating to the CoCs, including the status, can be verified against CBs’ online directories.

   1. For products with valid CoCs at the date of delivery to the project site, i.e. not suspended, terminated, expired or withdrawn, these are permitted to be used in Singapore.

   2. For products with CoCs that are not valid on the date of delivery to the project site, i.e. suspended, terminated, expired or withdrawn, usage of these products in Singapore is prohibited.

   3. Notwithstanding (1), for products with CoCs that were valid on the date of delivery, but are subsequently withdrawn, usage of the affected batches of such products in Singapore is subject to further assessment and investigation by SCDF and/or the CBs.

   4. Notwithstanding (1), for products with CoCs that were valid on the date of delivery, but are subsequently suspended for shelter-related reasons, e.g. pending investigation, it is not recommended that such products be used, as the investigation may show that the products are non-compliant and cannot be used (e.g. products that have been installed will need to be replaced/removed).

   5. CBs shall not allow the termination of a CoC which is suspended for shelter-related reasons, or which is under investigation by SCDF.

1. Regulated shelter products used in shelter works shall be certified by a local certification body accredited by SAC.

2. Regulated shelter products shall be accompanied by test reports from testing laboratories accredited by SAC or recognised by SAC via the International Laboratory Accreditation Cooperation (ILAC) MRA.

3. Any new CB participating in the PLS shall notify SCDF, in writing, of its accreditation by SAC, and submit its Certificate of Accreditation and Schedule issued by SAC for SCDF’s record. SCDF may request for additional information from the CB.

1. General Requirements

   CoCs issued for products intended for use in Singapore shall bear SAC’s accreditation mark.

2. Information Submitted for New CoC Applications

   The following information, at minimum, shall be submitted to a CB for application of a CoC. Where the information/documents are not provided in English, an official English translation, endorsed by a Notary Public, shall also be provided:

   1. CoC applicant details, including:

      1. Unique Entity Number (UEN) issued by the Accounting and Corporate Regulatory Authority (ACRA), or foreign equivalent, where applicable.

      2. Full names of the company directors, or equivalent.

      3. Name, address, contact number and email address of the company.

      4. Where the applicant is a foreign company, the details of the appointed local representative, for parts (1)(a) through (1)(c) shall also be included.

      5. Proof of partnership between the local representative and foreign CoC holder.

   2. Manufacturer’s details, for all the manufacturing plants of components of the regulated shelter product affecting shelter-related requirements, including:

      1. Country, name, address, contact number and email address of the manufacturer.

   3. Certification scheme details, including:

      1. Product category as classified under Table 8.1.

      2. Certification scheme, according to Clause 8.2.7.

   4. Product details, including:

      1. Brand and model, as determined by the manufacturer.

      2. Density and weight, where applicable, measured in kg/m3 and kg, respectively.

      3. Dimensions, where applicable, measured in mm.

      4. Latest product catalogue stipulating the specifications and user instructions.

   5. Details of type tests, including:

      1. The reference number of the test report.

      2. Test standards (including version of the test standard, i.e. year) which the product is tested to.

3. Documents Submitted for New CoC Applications

   The following documents shall also be submitted for CoC applications:

   1. Test reports, including the full type test reports and other test(s) required by the CB (e.g. material tests), which shall be:

      1. In full colour.

      2. Bear the brand and model of the regulated shelter product.

   2. For each test report, the credentials of the accredited laboratory which issued the test report, including:

      1. Documentation that the test laboratory is accredited by SAC or recognised by SAC via ILAC MRA.

      2. The accreditation scope indicating the test laboratory is accredited to perform such a test.

4. Information and Documents Submitted for Renewal of CoC

   CoC holders shall submit the information stipulated in Clause 8.3.5b.(1) and (2) and provide the date of issue of the very first CoC that had been issued for the product (i.e. “Original date of issue”). The CB shall make an assessment on whether there is a need to submit information stipulated in Clause 8.3.5b.(3) – (5), as well as documents stipulated in Clause 8.3.5c.(1) and (2). CB may require submission of any further information/documents as it deems fit.

1. Serial labels affixed to certified shelter products shall be water-proof and tamper-proof, and shall include a Quick Response (QR) code that stores the following information on an online database, which can be read by scanning the QR code:

   1. CoC holder company name.

   2. CoC holder ACRA UEN.

   3. CoC reference number.

   4. Brief product description.

   5. Exact location, including unit number, where applicable, where the regulated shelter product is installed.

   6. The status of the label (“valid” or “void”).

Note: The status of the label will be ‘void’ if SCDF detects discrepancies relating to the use of serial labels and digitally voided the serial label.

2. The following information shall be printed on the label itself:

   1. Product category.

   2. Unique serial number.

   3. CB’s logo or CB’s certification mark.

1. In the event that the serial labels are missing or damaged, a police report shall be lodged before replacement labels can be obtained from the CBs. A copy of this report shall be furnished to the CB, when requesting for replacement of labels.

2. An investigation by the CB shall also be conducted on the nature of the damage and/or loss, with the findings reported to SCDF for accountability.

Exemption: If labels are returned to the CB with the serial numbers still legible, a police report is not required.

Where shelter works involve the use of regulated shelter products, Qualified Persons shall carry out inspections of the shelter products, including but not limited to, the following:

1. Verify that the regulated shelter product(s) have valid CoC(s) and that the CoC(s) match exactly with the products used.

2. Verify that the regulated shelter product(s) are affixed with serial labels, if said products are stipulated to have labels in Table 8.1.

3. Where there are serial labels, verify that the serial label affixed on the product, are accurate and match exactly with the product.