Upcoming changes in NBC 2016 Part 4 ANNEX J (Clause 6.4.4) J-8 & J-9

As on date 16-08-2025, latest version of NBC 2025 still not released. This post is tentative only. Latest version of NBC 2025 is applicable for existing buildings when they are altered (see clause 12.4 of Part 2) or in the opinion of the authority constitute a hazard to the safety of the adjacent property or to the occupants of the building itself or are unsafe. 

Annex J For FIRE AND LIFE SAFETY REQUIREMENTS FOR METRO STATIONS.

• J-1 APPLICATION AND SCOPE

• J-2 TERMINOLOGY

• J-3 GENERAL

• J-4 LIFE SAFETY REQUIREMENTS

• J-5 EGRESS PROVISIONS

• J-6 FIRE SEPARATION AND COMPARTMENTATION

• J-7 OTHER SPECIFICS REGARDING SAFETY REQUIREMENTS

• New upcoming J-8 POWER SUPPLY SYSTEM

• New upcoming J-9 EMERGENCY LIGHTING SYSTEM

J-8 POWER SUPPLY SYSTEM

In NBC 2016 Part 4 says “the back-up/emergency power supply shall have a capacity to cater all critical loads such as emergency lighting, protective signalling system, communication system, fire station and control room, lifts providing required egress capacity, etc.”

Now upcoming NBC 2025 Part 4 under Annex J-8 says 

J-8.1 General

The Auxiliary Substation at Metro stations can be provided at any location, for example, Ground Level, Concourse Level, Platform Level, etc. The access for dismantling and replacement in future and ease of operation and maintenance of the equipment are to be ensured.

 J-8.2 Uninterrupted Power Supply (UPS) System

The UPS shall be an online parallel redundant system with battery back-up for emergency power supply. The batteries shall provide backup for minimum 90 minutes. If, DG set power backup to UPS is provided, the battery backup time shall be suitably selected. 

J-8.3 Back-up or Emergency Power supply

• The back-up/emergency power supply shall have a capacity to cater all critical loads such as emergency lighting, protective signaling system, communication system, station control room/fire command centre, lifts providing required egress capacity, etc.

• Power supply to these systems and equipment shall be from normal and emergency (standby generator power sources with changeover facility).

• If the power supply is taken from HT source and HT generation, the transformer shall be selected with standby capacity to ensure continuity of power supply to such systems. Where parallel HV/LV supply from a separate independent source is provided with appropriate transformer for emergency, the provision of Diesel Generator for emergency supply may be waived at the discretion of Metro Authority. In such a scenario, in case of failure of Mains power, the transfer to emergency power supply should be automatic and within 10 s for ensuring uninterrupted supply to emergency systems. 

J-8.4 Cables

• Fire resistant/survival, low smoke zero halogen, copper conductor, armoured, XLPE insulated cables shall be used at enclosed stations for fire and life safety equipment like Fire Alarm System (FAS), Tunnel Ventilation Fans, Smoke Extraction Fans, Staircase Pressurization Fans, fire pumps, emergency lighting, etc.

• All cables and wiring used for fire and life safety equipment shall have a 3 h fire survival capability at 950 °C.

• For all other essential services at enclosed stations like Chillers, AHU, normal lighting, Chilled Water pumps etc. flame retardant, low smoke zero-halogen (LSZH), armoured, XLPE insulated Aluminium/copper conductor cables shall be used.

• At open stations, flame retardant, low smoke halogen free (FR, LSH), armoured, XLPE insulated Aluminium/copper conductor cables shall be used for power supply.

• Fire alarm system signalling loop circuit (SLC) cable must be in red colour. Other hand Power cable must be in black colour.

 J-9 EMERGENCY LIGHTING SYSTEM

•  LED lighting fixtures shall be used for lighting at Metro stations.

• Emergency illumination shall include illumination of means of egress, illuminated exit signs, and all other luminaires specified is necessary to provide required illumination. Emergency lighting systems shall be designed and installed so that the failure of any illumination source cannot leave in total darkness any space that requires emergency illumination. Emergency lighting shall not provide less than average of 10 lux. Minimum illumination of 10 lux shall be maintained on egress route.

• Fire resistant (FR), low smoke and zero halogen (LSZH) copper conductor wires shall be used for wiring of emergency lighting system at underground stations. Emergency lighting system (ELS) circuit shall have 3hr fire survival (FS) capability at 950°C.

• Out of total light fixtures installed at any station, at least 30% of the total lights, all uniformly distributed shall be connected to emergency power source, that is, UPS.

• Emergency lighting shall be powered from a source independent of that supplying the normal lighting.

 REFERENCE:
CED 46(26992) WC - Draft Code for Comments Only.