150mm Rising Fire Mains and R.I.C.E Firefighting Tactics 2020

In May/June 2020 the revised BS PD 7974-5 (Application of fire safety engineering principles to the design of buildings Part 5: Fire and rescue service intervention) will again provide an option for the UK Fire and Rescue Service (FRS) to require 150mm rising fire mains, with optional twin controlled outlets at every floor level, in fire engineered buildings (including flats with extended corridors protected by mechanical ventilation). This is something that must first be agreed by the local FRS fire safety department at the QDR stage. This option has in fact existed ever since BS 5306:1976 first proposed twin outlet 150mm rising mains but it has rarely been a provision requested by the FRS.

 However in 2006, following several serious high-rise fires in the UK, DCLG Fire Service Circular 32/2006 informed all fire services that they should adopt fire-fighting techniques at all high-rise incidents that provide for an additional covering jet to protect fire-fighting personnel actively involved in firefighting or rescue operations. It stated that this second jet should come from the Bridgehead, two floors below the fire. Since then the ‘second jet’ has repeatedly been responsible for allowing smoke to enter the stairs to further compromise the escape stairs. In single stair buildings this has proved life critical.

In 2014, as members of the review committee, Kent Fire and Rescue Service developed the design guidance within the revised BS PD 7974:5 that would enable the 150mm main with double outlets at each level to again be requested during the design stages of fire engineered buildings. In 2020 this may now be a requirement in specific buildings if the FRS choose to utilise the design option.

R.I.C.E Firefighting Tactics

At the same time Kent FRS were developing national fire engineering design guidance, their firefighting tactics and primary command procedures were being further developed to enhance their tactical approaches and protect the vertical escape channels more effectively, whilst still meeting the requirement to provide a second (covering) jet at the fire floor. At the very core of their tactical approach was the analytical command tool R.I.C.E where the overriding objective was to establish, protect and maintain a means of escape and firefighting access using the stairs.

The primary commander on scene undertook the usual information gathering to increase situational awareness and assist plan formulation. This is all very dynamic and generally occurs in very short time-frames. Quite often, key decisions are made within less than a minute. The RICE command mnemonic allows four options that are targeted in meeting all generic internal approaches –

R – Rescue

I – Intervention

C – Containment

E – Evacuation

The tactical approach follows the KFRS RICE guidance

• RESCUE – If there is clear reliable and confirmed information that assure either a person or persons are trapped inside a flat, or an immediate firefighting intervention may save further lives and/or prevent a worsening fire situation from getting out of control (a sprinkler controlled fire with limited supply is an example), an immediate attack may be made using one hose-line (jet), prior to a cover line being in place. This single line entry is primarily at the discretion of the Incident Commander. In such situations, the corridor/lobby has now become the fire compartment and any cover line subsequently laid should come from the floor below and only be laid as far as the stair door to avoid unnecessary amounts of smoke leaking into the stairwell. This can be advanced into the accommodation to assist as needed but must be carefully coordinated with stair protection strategies, knowing that firefighters and occupants may still be in the stair. Prior to advancing a hose-line through a stair door, the ICs permission should first be obtained, and a check should be made for persons in the stair, particularly above the fire floor.
•  INTERVENTION – Without the above ’triggers’ determining the need for rapid deployment, a firefighting intervention requires both attack and cover (safety) hose-lines in place before compartment (flat) entry should occur. Both lines are laid from the fire floor and within the accommodation corridor/lobby to protect the stair from smoke infiltration. If twin outlets are provided from a 150mm main that alleviates having to bring the dividing breeching. If the outlet is in the stair the provision of a portable smoke blocking curtain at the stair door is necessary, providing it does not hinder any automated mechanical ventilation air supply from the stair.
• CONTAINMENT – There are situations where the fire must be contained or isolated, slowing or preventing its spread rate. It is critical that an external observer is located within sight of the involved building face to report on wind speed/direction, window opening status, fire behaviour indicators and any apparent post flashover conditions to the Incident/Bridgehead Commander and interior firefighting teams. If a wind is heading directly into a window (noted by pulsing flames or smoke emissions at the opening) then it may be more appropriate and safer to delay any firefighting intervention, to enable local evacuation of any primary risk zone to be prioritised. Depending on the strength of the wind, it may be a situation to utilise ‘floor below’ high-rise nozzles or even allow the fire’s fuel-load to burn down before entering to extinguish the fire.
• EVACUATION – In situations where wind is heading into the fire, or a fa?ade fire has spread beyond three floors (or into the roof void, particularly of a lightweight metal or timber-framed building), total building evacuation may precede any internal firefighting intervention. At the same time, external firefighting may be a viable option to control or slow fire spread whilst evacuation is occurring.

Risk Assess the Lobby for Entry

Firstly and most importantly, in 45 years of firefighting research I am not aware of ANY fire anywhere, where firefighters have died or been injured where the number of doors (or floors) between them charging a hose-line and leaving the stair or entering a fire compartment, had any negative impact.

There have been fires where external wind or other foreseeable events caused life loss. There have been fires where firefighters have been caught in common areas by unforeseeable extreme fire events. There have also been fires where firefighters exposed themselves to unnecessary risk in smoke-logged corridors without the protection of a charged hose-line However, it is not the number of doors between them and the fire that has been the determining factor for once they have begun their advance towards the fire, it is only careful pragmatic and ongoing risk assessment that may reduce any likelihood of exposure to risk. Taking lines from below the fire floor creates additional physiological stress on firefighters, increasing body core temperatures even prior to entering a heated environment. It is also more demanding on resources for effective hose management.

What is apparent though is that there seems some clear links back to traditional firefighting tactics in tenements and older six or seven storey buildings. It was the case in the 1960s -70s that much of the firefighting was undertaken by laying hose-lines externally by hauling aloft, or up escape ladders to the floor below the fire, from where an unprotected stair was entered to access the fire above. Today we have fully protected (two hours) Firefighting Shafts and it may be life critical that this level of protection is maintained throughout firefighting operations.

150mm Rising Fire Mains – Twin Outlets at each Level

The BS PD 7974-5 wording in place in the 2014 version is as follows –

8.5.4 Where fire service intervention is to be considered as part of the engineering strategy for a building, the effectiveness of such an intervention may be improved in some cases by the provision of 150 mm internal fire mains with twin outlets at every floor as opposed to single outlet 100 mm mains. The reason for this is because any increase in calculated fire-fighting water demands may be more readily available for deployment per m2 of open-plan floor space. The additional provision of protected lobbies allows stairs to remain smoke free for longer and enable fire-fighters to deploy two hose-lines at the fire floor and intervene far more quickly and effectively. In open-plan floor space, time to deployment may be critical.

The wording in place on revised BS PD 7974-5 guidance, as published from May/June 2020 is as follows -

7.8.2 In some cases, the fire service might demonstrate a preference for specific facilities, such as rising fire mains, to be located away from the stair in residential buildings. In such circumstances, a preferred location might be within a ventilated protected lobby/corridor. According to an on-scene risk assessment, this could enable firefighters to lay initial attack hose-lines from the fire floor itself, reducing the likelihood of smoke infiltrating into the firefighting stairwell. This preference is particularly important in single stair residential buildings but might also feature in multi-stair residential buildings. However, any such deviation in this respect, where firefighting main design is not specifically in accordance with typically prescribed regulatory guidance or standards, should take place at the QDR stage and local fire service agreement is essential.

Such enhancements might serve to assist firefighting on upper floors of tall buildings >18 m (only when agreed by the fire service at the QDR) and may include:

a) 150 mm rising mains, enabling four inlets at the access level to deliver greater quantities of water from to the fire floors and allowing additional pumps to augment the supply using an alternative second hydrant where needed.

b) two separate flow-controlled outlets at each floor level, allowing two hose-lines to be taken from each rising main.

c) the locating of rising main outlets away from the stair, into protected corridors or firefighting lobbies in residential buildings, enabling firefighters to prevent or reduce smoke infiltrating into protected escape routes and firefighting stairs.

d) in such situations, riser outlet valves should be located immediately adjacent to the firefighting stair door, but never further than 1 m from the door. They should be contained within a box in accordance with BS 5041, also being large enough to house twin controlled outlets, if installed; the marking of charging pressures on/at the inlet to the rising main, to assist firefighters to determine the maximum charging pressure of any particular dry riser (currently 12 bar); and

e) the marking of individual stairwell and floor numbers on landings, to link up with multiple banks of rising main inlets that might exist in large complexes, to assist the fire service in wayfinding and charging the correct main.

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