This set of fire safety requirements shall be applicable to roof-mounted PV installations.
a. For PV installations on the roof, at least one exit staircase shall be provided. Where the area of non-habitable roof 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.2.3.12 and leading to the circulation area of the floor below shall be provided.
b. For existing buildings which are carrying out the installation of PVs on the roof level where the provision of single exit staircase is not feasible, a portable sturdy ladder to the roof access shall be provided. Single storey buildings with roof height not more than 12m or inaccessible pitched roof up to 24m from grade level are not required to provide a sturdy ladder, if there is a fire engine accessway fronting this installation.
c. The computation of travel distance for roof areas which are open to the sky for any purpose group (except PG I) can be based on the requirement for sprinkler-protected compartments/buildings.
d. 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.
10.2.3 Fire resistance of PV modules
a. The standard IEC 61730-2 stipulates the fire test for PV modules. The characteristics assessed in the fire test establish the fundamental fire resistance of PV modules mounted over an existing roof. A minimum fire resistance rating Class C shall be provided for any roof-mounted PV module.
b. System components associated with the PV modules, such as wirings and switchboard assemblies, shall comply with the installation requirements as stipulated in SS CP 5.
10.2.4 Design and installation criteria
a. The sub-array for the PV installations shall be limited to a maximum size of 40m by 40m.
b. A clearance of 3m around the access/hatch opening and in front of exit door (of exit staircase) shall be provided.
c. For a roof without perimeter parapet/railing, a clear width of not less than 2.5m shall be maintained along the perimeter aisles/gangways. For a roof with perimeter parapet/railing of height not less than 900mm, a clear width of not less than 1.5m shall be provided along the perimeter aisle/gangway.
d. There shall be a minimum of 1.5m separation between arrays.
e. There shall be no storage or services below the PV installation.
f. 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 10.2.4)
10.2.5 Emergency disconnection
a. 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.
b. Operating instructions for the emergency shut off system shall be placed at a height of between 1.5m to 2m from the floor and clearly displayed near to the emergency shut-off system.
c. 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 floor and displayed close to the access openings or the exit staircase from the roof.
Diagram 10.2.4 : Solar Panels Installation Criteria