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Fire IQ: January 2012


January 6, 2012
By Peter Hunt

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I have experienced several highrise fires in my career, and I have never worried much about them.

I have experienced several highrise fires in my career, and I have never worried much about them. The unit of origin was usually easy to locate; typically, the fires were well compartmented, ensuring against extension to exposure units and the common hallway; most were brought under control quickly using a single 45-millimetre hoseline; and smoke conditions were dealt with efficiently (our department is well versed in techniques and equipped to ventilate high buildings). These factors, supported by a strong incident-command system and comprehensive highrise manual, gave me confidence.

That all changed recently when my department experienced three close calls (one involving me and my crew) due to a complete loss of water supply during highrise firefighting operations.

In these cases, there were no injuries to civilians or firefighters and crews quickly regrouped to complete extinguishment, but an interruption in the water supply – particularly when operating from a standpipe system (where a backup line is often not stretched) – could have catastrophic results.

In hindsight, the events here in Ottawa could have been anticipated, and once identified, the department quickly addressed the contributing factors. Loss of water could happen to you and sharing our experiences might prevent a similar occurrence elsewhere.

Upon investigation, it was apparent that all three failures in water supply were due to debris and sludge that had accumulated in the standpipe systems and travelled through the riser into the 45-millimetre fire hose, clogging the nozzle. There was surprisingly little warning for the attack crew and the blockage was complete in all three cases.

Some of you may operate solid-bore nozzles on your apparatus or highrise packs, but most of us have fog nozzles. You can pump just about anything through a solid-bore tip, but ball-valve and sliding-barrel fog nozzles are subject to clogging at the pattern selector. In our case, our highrise nozzle had a sliding barrel shutoff and a pre-screen at the coupling to capture contaminants. Upon investigation, it became clear that this was not an appropriate nozzle for highrise fire fighting and it was replaced with a more traditional ball-valve-controlled nozzle without a screen.

While there is no industry standard, many major metropolitan fire departments with a lot of experience fighting highrise fires operate 65-millimetre hoselines and solid-bore nozzles in order to prevent clogging and move big water at low pressures. The trade-off is a very heavy line requiring a lot of manpower. Many of us don’t have the luxury of that kind of staffing and have opted for the easier-to-operate 45-millimetre line.

Hoseline size is often influenced by staffing levels, but nozzle selection is frequently influenced by tradition, culture and experience. My department has limited experience with solid-bore nozzles and, consequently, is reluctant to place them into service on initial attack hoselines, despite their proven track record in many applications, including highrise fire fighting.

Regardless of hose size and nozzle type, your highrise policies must ensure that a backup line is stretched or at least brought to the fire floor. Remember, most highrise fires will be controlled using a single line, but burst hoses, clogged nozzles, fire spread to exposure units or into the common hallway, wind-driven fires, or other unforeseen events, will occasionally require that subsequent lines be placed into operation in a hurry. You must be prepared.

This raises the obvious question of where the second line should be connected. Choices include down the hall, the floor below, or simply at the original standpipe with a wye. Do you have enough manpower, highrise hose or the necessary appliances to accomplish this?

Another issue concerning standpipe operations is the requirement to flush the standpipe system prior to connecting and charging the attack hoseline. My colleagues and I cannot say for certain that a thorough flushing of the standpipe system would have prevented the loss of water supply that we experienced. The contaminants that eventually reached and clogged the nozzle probably travelled several floors and would have required that we flood the common hallway prior to hooking up. This kind of water damage would be difficult to justify to building owners at a pot-on-the-stove fire, but would go completely unnoticed at a major highrise fire. Since the door to the unit of origin can often hide conditions inside the apartment, company officers may be required to open the door (or force it open) and assess interior conditions prior to giving the order to flush or not flush, and then charge the standpipe.

In most jurisdictions, the theft of caps from fire-department standpipe connections is rampant. Building owners typically are not motivated to replace them and the ensuing accumulation of contaminants can greatly contribute to the problem discussed here. Fire departments must enlist the support of firefighters, fire inspectors and even bylaw officers to ensure that all buildings are checked and owners are reminded of their obligation to cap these connections.

Most people will never experience a complete loss of water supply while fighting a highrise fire, but some will. Once you have, you will never fully trust standpipes again, and you will understand the importance of choosing the correct nozzle, giving consideration to flushing the system and ensuring that a second line is available to be placed quickly into operation. You might even remind building owners to replace the caps on their fire-department connections. Most importantly, take this opportunity to thoroughly review your department’s highrise procedures, revise them if necessary and check your nozzles.


Peter Hunt, a 29-year veteran of the fire service, is a captain in
the Ottawa Fire Department’s suppression division. He can be reached at
peter.hunt@rogers.com


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