Section 16: Fire mains and hydrants

Introduction

16.1 Fire mains are installed for the fire and rescue service to connect hoses for water. They may be either of the following.

a. The ‘dry’ type, which are both of the following.

i. Normally kept empty.

ii. Supplied through a hose from a fire and rescue service pumping appliance.

b. The ‘wet’ type, which are both of the following.

i. Kept full of water.

ii. Supplied by pumps from tanks in the building.

There should be a facility to replenish a wet system from a pumping appliance in an emergency.

Provision of fire mains

16.2 Buildings with firefighting shafts should have fire mains in both of the following.

a. The firefighting shafts.

b. Where necessary, in protected escape stairs.

The criteria for providing firefighting shafts and fire mains are given in Section 17.

16.3 Buildings without firefighting shafts should be provided with fire mains where fire service vehicle access is not provided in accordance with Table 15.1. In these cases, outlets from fire mains should be located as described in paragraph 16.4, with a maximum hose distance of 45m from the fire main outlet to the furthest point, measured on a route suitable for laying a hose. Stairs do not need to be designed as firefighting shafts.

Design and construction of fire mains

16.4 If a firefighting shaft is provided, outlets from fire mains should be within the protected stairway or protected lobby (see Diagram 17.1).

16.5 Guidance on the design and construction of fire mains is given in BS 9990.

16.6 Buildings with a storey more than 50m above fire service vehicle access level should be provided with wet fire mains. In all other buildings where fire mains are provided, either wet or dry fire mains are suitable.

16.7 Fire service vehicle access to fire mains should be provided as described in paragraphs 15.4 and 15.5.

Provision of private hydrants

16.8 A building requires additional fire hydrants if both of the following apply.

a. It has a compartment with an area more than 280m2.

b. It is being erected more than 100m from an existing fire hydrant.

16.9 If additional hydrants are required, these should be provided in accordance with the following.

a. For buildings provided with fire mains – within 90m of dry fire main inlets.

b. For buildings not provided with fire mains – hydrants should be both of the following.

i. Within 90m of an entrance to the building.

ii. A maximum of 90m apart.

16.10 Each fire hydrant should be clearly indicated by a plate, fixed nearby in a conspicuous position, in accordance with BS 3251.

16.11 Guidance on aspects of provision and siting of private fire hydrants is given in BS 9990.

Alternative supply of water

16.12 An alternative source of water supply should be provided where any of the following apply.

a. No piped water supply is available.

b. Pressure and flow in the water main are insufficient.

c. An alternative source of supply is proposed.

16.13 The alternative source of water supply should be one of the following, subject to consultation with the local fire and rescue service.

a. A charged static water tank with a minimum capacity of 45,000 litres.

b. A spring, river, canal or pond that is capable of fulfilling both of the following conditions.

i. Providing or storing a minimum of 45,000 litres of water at all times.

ii. Providing access, space and a hardstanding for a pumping appliance.

c. Any other water supply that the local fire and rescue service considers appropriate.