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Clause 10.2 - SOLAR PHOTO-VOLTAIC (PV) INSTALLATION

10.2.1 Roof-mounted PV installations

Effective Date: 1 Mar 2022

a. General

This set of fire safety requirements shall be applicable to roof-mounted PV installations. For PV installations on the roof of PG I buildings, the requirements are stipulated in Cl.9.1.1d.

b. Means of access

Effective Date: 1 Mar 2022

(1) For access to PV installations on the roof (excluding non-PV areas), at least one exit staircase shall be provided. Where the area is large and one-way travel distance to the exit cannot be met, an additional cat ladder or ship ladder adequately separated from the exit staircase, in accordance with  Cl.2.2.11 and leading to the circulation area of the floor below shall be provided, except for the following:

(a) Single storey buildings with roof height not more than 12m or  inaccessible pitched roof up to 24m from grade level are required to provide a portable sturdy ladder or cat/ ship ladder. If there is a fire engine access road serving roof height not more than 12m or fire engine accessway serving inaccessible pitched roof exceeding 12m and up to 24m is provided, access to PV installation is not required. 

(b) External/ open-sided overhead bridge/ shed/  linkway/ walkway with clear width not more than 6m, roof height not more than 12m and without any commercial activities.

(2) For buildings where plans submission on the installation of PVs on the roof level was made on or before 16 June 2016, the provision of single exit staircase is not required. Instead, a cat/ship ladder to provide access to the roof shall be provided.

(3) The computation of travel distance for roof areas which are open to the sky for any purpose group can be based on the requirement for sprinkler-protected compartments/buildings.

(4) All access hatches, if provided, shall be readily accessible from the roof. The access hatch opening shall have a minimum clear width of 1m in diameter.

c. Fire performance of PV modules

Effective Date: 1 Mar 2024

(1) PV modules shall meet a minimum of Class C for both spread of flame and burning brand tests, in accordance with IEC 61730-2.

(2) System components associated with the PV modules, such as wirings and switchboard assemblies, shall comply with the installation requirements as stipulated in SS 638.

d. Design and installation criteria

Effective Date: 1 June 2020

(1) Each array of a PV installation shall not exceed the maximum dimensions of 60m x 40m.

(2) A clearance of 3m around the access/ hatch opening and exit doors shall be provided.

(3) Access aisles of minimum clear width of 1.5m shall be provided such that no part of any PV array is more than 20m from any of them. Where the access aisle abuts the edge of the roof, the clear width of the access aisle shall be at least 2.5m unless a perimeter parapet/railing of height not less than 900mm is provided.

(4) Storages or services located below PV arrays excluding those stated under Cl.10.2.1b.(1)(b), shall be separated from the PV arrays as follows:

(a) For sprinkler-protected space below arrays, a non-combustible separation shall be provided. 

(b) For sprinkler-protected space below arrays, if the PV modules comply with Cl.10.2.2b., no separation is required.

(c) For non-sprinkler-protected space below arrays, a 1-hr fire-rated separation shall be provided.

(d) For non-sprinkler-protected space below arrays, if the PV modules comply with Cl.10.2.2b., a non-combustible separation shall be provided.

(5) PV modules, wirings, switchboard assemblies and other equipment shall not cover any ventilation system on the roof (e.g., smoke control/ extraction systems or air well).

(See Diagram 10.2.1.d.)

e. Emergency disconnection

(1) Manual emergency shut-off system for the disconnection of the PV modules shall be provided on both the AC-power side (typically where inverters are placed) and the switch room side.

(2) Operating instructions for the emergency shut off system shall be placed at a height of between 1.5m to 2m from the finished floor level and clearly displayed near to the emergency shut-off system.

(3) Simplified site plan with the position of PV modules and system circuit diagrams shall be placed at a height of between 1.5m to 2m from the finished floor level and displayed close to the access openings or the exit staircase from the roof.

10.2.2 Wall-mounted PV installations

Effective Date: 1 Mar 2022

a. General

Effective Date: 1 Mar 2022

This set of fire safety requirements shall be applicable to wall-mounted PV installations.

b. Fire performance of PV modules

Effective Date: 1 Mar 2022

(1) PV modules shall comply with all of the following requirements:

(a) the outer layers shall be constructed of glass or non-combustible material;

(b)   a minimum of Class B with Fire Growth Rate (FIGRA) ≤ 70 W/s under EN 13501-1;

(c)  a minimum of Class A for both spread of flame and burning brand for Module Safety Tests (MST) 23 (fire test), in accordance with IEC 61730-2;

(d)  at least a pass for MST 22 (hot spot endurance test), MST 25 (bypass diode thermal test) and MST 26 (reverse current overload test), in accordance with IEC 61730-2;

(e) Junction boxes shall comply with IEC 61730-1 for glow wire test and achieve flammability class V-1 for outer accessible parts, flammability class HB for inner parts, flammability class 5V on the end-product and the result is assessed in accordance with flammability class 5VB; and

(f) Cables used shall comply with IEC 61730-1 for vertical flame propagation.

(2) System components associated with the PV modules, such as wirings and switchboard assemblies, shall comply with the installation requirements as stipulated in SS 638.

c. Design and installation criteria

Effective Date: 1 Mar 2022

(1) PV installations shall comply with all of the following:

(a) PV installations shall be mounted on external walls of at least 1-hr fire resistance.

(b) PV installations shall be installed at least 5m vertically above grade level. Alternatively, PV installations can be installed 3m above grade level, if a 1-hr fire-rated horizontal projection that extends at least 600mm from the building is installed beneath the PV installation.

(c) PV installations shall be installed away from any unprotected openings, or combustible material/ construction within 1.5m horizontally or within 3m vertically, or adjacent to or facing it. Alternatively, the 3m vertical separation can be exempted if a 1-hr fire-rated horizontal projection that extends at least 600mm from the building is installed between the PV installation and the unprotected opening.

(d) PV installations located adjacent to exit staircases shall comply with Cl.2.3.3a.(3) or Cl.2.3.3b.(2)(b).

(e) Only components (i.e., cables, junction box, etc.) serving the PV installations are allowed to be run between the PV modules and the external wall.

(f) All cables and related components shall be housed in a non-combustible conduit. The positive and negative DC cables shall be installed in separate containments.

d. Emergency disconnection

Effective Date: 1 Mar 2022

(1) Manual emergency shut-off system for the disconnection of the PV modules shall be provided on both the AC-power side (typically where inverters are placed) and the switch room side.

(2) Operating instructions for the emergency shut-off system shall be placed at a height of between 1.5m to 2m from the finished floor level and clearly displayed near to the emergency shut-off system.

(3) A simplified site plan with the position of PV modules and system circuit diagrams shall be placed at a height between 1.5m to 2m from the finished floor level and displayed close to the switch room or FCC, if applicable.

10.2.3 Wall-integrated PV installations

Effective Date: 1 Mar 2024

a. General

This set of fire safety requirements shall be applicable to wall-integrated PV installations, where PV is integrated into the building such as windows or curtain walls.

b. Fire performance of PV modules

PV modules shall be in accordance with Cl.10.2.2b..

c. Design and installation criteria

PV installation shall comply with the following:

(1) All spaces abutting/ facing PV installations shall be fully protected by an automatic sprinkler system or automatic fire extinguishing system, unless they comply with all of the following conditions:

(a)  the building does not exceed 12m in habitable height;

(b)  the building is protected by an automatic fire alarm system compliant with SS 645; and

(c)  the building does not contain healthcare occupancy (inpatient).

(2) PV installation located adjacent to exit staircases shall comply with the Cl.2.3.3a.(3) or Cl.2.3.3b.(2)(b).

(3) All cables and related components shall be housed in a non-combustible conduit. The positive and negative DC cables shall be installed in separate containments.

(4) The opening occurring at the junction between the edge of a structural floor and the wall-integrated PV shall be sealed to prevent the spread of smoke and flame from the lower floor to the upper floor via the opening. Fire stopping materials for sealing the openings shall have the same fire resistance rating as the elements of structure.

d. Emergency disconnection

Emergency disconnection of the PV modules, it shall be in accordance with Cl.10.2.2d..

Diagram 10.2.4 (1 June 2020)

Diagram 10.2.1d. : Roof-mounted PV Installation Criteria