Let’s get into some of the nuts and bolts of ensuring that a stationary fire pump will operate during a fire and be considered a reliable source of water. This article is specifically written about to diesel engine driven fire pumps. The intent is to generate some thoughts around the proper assessment of diesel engine driven fire pumps in order for them to be considered reliable during a fire situation.
In the last article, I pointed out the basics of gaining access to the fire pump room and some of the requirements that are mentioned in NFPA 20. It should be noted that a diesel engine fire pump room is required to be sprinklered per NFPA 20. Also, the room or building that houses the fire pump should be protected from flood waters, explosions and other external effects that can affect the operation of the fire pump.
Chapter 11 of NFPA 20 spells out the requirements of a diesel engine driven stationary fire pump. Some specific areas that should be reviewed when visiting the fire pump room are as follows:
How was the diesel fuel tank sized? NFPA 20 recommends that it contains a one gallon per engine horsepower, five percent for expansion and five percent for sump. The sizing of the fuel tank is based on a fire that will last eight hours. It should be noted that some occupancies, like a large refinery, may require an even larger tank as the anticipated fire duration may extend 12 to16 hours. The diesel fuel tank should be located inside the fire pump room to maintain a steady temperature. During the review of fuel supplies for the diesel engine driven pump, the emergency responder should inquire about the removal of five gallons of fuel from the tank on an annual basis. The removal of five gallons of fuel from the tank sump lessens the chance that contaminants will enter the fuel filter and potentially disrupt the driver’s operation.
The location of the batteries should be noted such that if the emergency responder enters the fire pump room and needs to start the engine without the use of the controller, he is not exposed by the batteries. Having said that, the emergency responder should either be able to operate the engine without the use of the controller or make sure that there will be someone in attendance who can operate the engine manually. A set of instructions attached to the driver is very helpful during these emergency situations.
The pump room itself should be maintained at 40 degrees F or greater in order to prevent degradation of the batteries starting capacity. The diesel fuel located in the tank may gel at lower temperatures as well. Also, the room ventilation and combustion air louvers should be verified as operable.
There are only two items relative to the diesel engine driven pump that require electrical power. These are the engine block heater and the battery chargers located inside the engine controller. These two electrically operated items are critical to the reliable operation of the engine. Unfortunately, the block heaters have a high failure rate, for a multitude of reasons, so its operation should be verified.
There are basically only three ways that the diesel engine driven pump can be halted. One is if it runs out of fuel, another is if someone manually places the selector switch located inside of the controller in the off position or if the engine experiences an overspeed condition. Low oil pressure, high engine temperature will not halt the operation of the engine, which is unusual when dealing with diesel engines.
All the above-mentioned items should be part of the fire department or emergency response team’s pre-emergency plan. It’s always better to be prepared in advance and know the intricate details of how a diesel engine driven pump operates prior to the event.