Recently, an unfortunate event occurred in my former department. Two of our vehicles - an ALS unit transporting a patient and their family and a pumper truck responding to another alarm - collided at an intersection. The pumper truck had even rolled onto its side after impact. Thankfully, there were only minor injuries to all crew members involved in the accident, and they were sent home for the rest of their tour.
Subsequently, a longtime associate from USAR, FLTF2 asked me if I wanted to visit the station from which the two trucks responded. The purpose was to assist as part of a Critical Incident Stress Debriefing (CISD) team.
From my personal experience, there has never been anything more perplexing for new—and even experienced—drivers than understanding how to set a fire truck's mechanical relief valve. It’s important to use these devices regularly to assure that they remain in good working order.
There are only two items that control pressure on your hoselines: the throttle and the discharge gates. The relief valve is a very important safety feature that protects those working on or around hoselines from “over pressurization.” Too much pressure can prevent proper hoseline handling, including inadvertent movement when using master streams.
While newer pressure governors have become the accepted standard on newer fire apparatus, chances are you will still have to deal with mechanical relief valves on front-line fire apparatus or spare fleet vehicles.
Much like concern over the nation’s deteriorating roads, bridges and other transportation infrastructure, reports about lack of funding for aging and malfunctioning fire trucks and other apparatus are proliferating at an alarming rate. Financial hardships are forcing many departments to rely upon equipment nearing—or even at—obsolescence.
In turn, this ratchets up pressure on departments to ensure that maintenance checks and protocols are performed in as timely and complete a way as possible to maximize fleet and apparatus life, reliability and safety. Public safety watchdogs are keeping score on all of it. Underfunded departments doing the best with what they’ve got will be more readily excused when a malfunction occurs than those exhibiting negligence in their maintenance checks and repairs. Two examples below demonstrate the discrepancy.