The Apparatus Architect-Part 59 Overweight and Out of Shape-What Condition is Your Apparatus Fleet In?

During the past few months there has been a spirited national discussion about health care and the leading causes of obesity in adults across the country.  No matter which side of the political aisle you may be, there is little doubt that our nations health care system is in need of an overhaul.  The fire service has long ago recognized the importance of physical fitness through many programs including the sixteen Life Safety Initiatives promulgated by the National Fallen Firefighters Foundation. Among the sixteen initiatives the significance of being healthy and physically fit is summarized in the following statement: “Develop and implement national medical and physical fitness standards that are equally applicable to all firefighters, based on the duties they are expected to perform.” While many departments have adopted and implemented health and welfare programs for their personnel the apparatus that we utilize to deliver emergency services has unfortunately not received the same attention.

The National Fire Protection Association (NFPA) has several well established standards for use to reduce the opportunities for departments to purchase or operate overweight apparatus.  The 1901 Automotive Fire Apparatus Standard mentions in several areas the requirements placed both on the manufacturer and the fire department with respect to weight and axle loading.  Section 4.3 of the Standard lists the responsibilities of the fire department to determine the hose load, tools and equipment that will be carried on the apparatus.  Failing to provide this information results in the minimum equipment payload allowance listed in Table 12.1.2 to be utilized by the manufacturer when determining the required chassis gross vehicle weight rating for the apparatus.

So what does all this mean?  A department’s apparatus committee that is in the process of designing a rescue-engine needs to develop a comprehensive tool and equipment inventory with weights, including both space and weight allowances for future expansion. This inventory is then given to the prospective manufacturers to determine the appropriate axles, tires and suspension components that will safety carry the intended load on the vehicle, including personnel. 

Unfortunately, it is not difficult to find an overloaded piece of apparatus regardless of age or design characteristics. Over the past few years we have reviewed hundreds of in service units after they have been weighted by the department and identified the following:

  • A less than five year old custom pumper equipped with a 750 gallon water tank and 5.00 inch hose was overweight on the rear axle by more than 2300 pounds
  • An eight year old custom pumper tanker equipped with a 2000 gallon water tank with seating for six personnel.  When operating with a crew of six the front axle would be overloaded by almost 1200 pounds.
  • A seventeen year old custom rescue engine was overloaded on the front axle with no personnel on board and the rear axle within 800 pounds of the axle rating.
  • An aluminum body mini pumper with a chassis rated at 12,000 pounds was overloaded by 600 pounds on the rear axle.

Each of these department’s were unaware of their apparatus weights and axle loading until it was brought to their attention that the NFPA 1911 Standard requires that all units be annually weighted to confirm the in service weight of the apparatus. Chapter 16 of the NFPA 1911 Standard for the Inspection, Maintenance, Testing and Retirement of In Service Apparatus describes in detail the procedure for weighing the apparatus.  Most fire departments can access certified scales which are available at local transfer stations, sand and gravel companies and local salvage yards. State and local police agencies can also provide this service for the department to obtain the necessary information to validate the axle weights on each apparatus.

The annual verification of the in service weight on the apparatus is one of several testing requirements that should be conducted by the fire department or maintenance staff.  Overweight apparatus can impact the handling, braking and steering of the apparatus and is often indicted during routine operations.  Maintenance records may indicate that premature brake and tire wear on overweight apparatus and should the unit be involved in any type of accident the axle weights on the vehicle will certainly come into question.


Over the years certain types of apparatus have been more suspect of being overweight including converted fuel oil tankers that are converted into water tenders.  The frequency of tanker and tender accidents caused the U.S. Fire Administration to issue a detailed study of tanker operations.  Factors cited in the report included inadequate driver training, improper apparatus modifications and vehicle weights.  As a result of this study and other factors the NFPA 1901 Standard in the 2009 edition Section 4.15.3 requires that apparatus with a gross vehicle weight rating (GVWR) of more than 50,000 pounds or water/foam tanks greater than 1250 gallons are limited to a maximum road speed of 60 miles per hour.

While this reduction in road speed impacts newly built tankers, aerial devices and many rescue engine apparatus the reduction in speed does not imply that the apparatus can be safe to operate if the unit is overloaded.  While interstate truck commerce is regulated at a State level with respect to vehicle weights, many localities exempt fire apparatus or have an informal exemption from these regulations.  The responsibility to monitor the in service weight of your apparatus falls squarely in the hands of the fire department.  As the old adage states: “Ignorance of the law is no excuse!” Check to make certain what your state regulations are! An informal exemption will not hold up in a court of law if your actions are ever called into question.


Every fire department should develop a procedure to conduct annual in service weight testing of all apparatus and document these results.  The individual front and rear axle weights as well as the overall weight need to be compared against the ratings established when the apparatus was delivered.  This information can generally be found inside of the chassis cab where the original body builder would post the axle ratings based upon the lowest rated chassis component of the axle, tires, wheels and suspension.  Certain sizes of tires may have been certified for a higher weight capacity than those stamped on the tire sidewall as fire and emergency vehicles are considered to have an intermittent duty cycle.  If there are questions with respect to the components on your specific apparatus the manufacturer’s original Bill of Materials and component lists should be consulted to verify the actual weight ratings.

Departments that are in the process of specifying new apparatus should in addition to developing the tool and equipment inventory should include a requirement that each bidder provide a detailed weight analysis for the apparatus being proposed.  This documentation will indicate the anticipated front and rear axle loads for the vehicle showing the individual weights of cab and chassis, personnel, body compartments, hose, tools and fixed equipment and how these weights are distributed on each axle.

Using this weight analysis provides a starting point for the life cycle of the apparatus and should be used to verify the weight of the apparatus prior to acceptance by the fire department.  The documentation of the apparatus weight can also be utilized to verify the proposed tire, axle and suspension components that are being supplied by each vendor.

Like many things in life, fire apparatus does not tend to get lighter after several years of service.  With many fire and emergency departments proclaiming that they are an All Hazard Agency, this mission often includes an extensive array of technical rescue, hazardous materials and fire support equipment that can have an impact on vehicle weight and road performance.  Do not let the age, manufacturer or outward appearance of your apparatus fool you into thinking that the vehicle is not overloaded and safe for continued operation.  Weight, document and inspect each apparatus as your life and the safety of those around you depend upon it, every time your respond.  

Photo captions for AA Part 58:

#1. This apparatus was one of the first mini-pumpers delivered to the Syracuse, New York Fire Department in 1971.  Like most mini-pumper units of this vintage they were overweight and suffered from suspension and brake issues.

AA PART 59- Photo #1

Photo by Tom W Shand

#2.  The spring pictured here came off of a pumper with less than 3 years of in service use.


Photo by Mike Wilbur

#3.   A brake job being performed by FDNY mechanics on a Mack Tower


Ladder.  If your apparatus needs brakes at fairly regular intervals that could be a tell tale sign of an overweight apparatus.

Photo by Mike Wilbur

 N.F.P.A. 1901 TABLE 12.1.2




ž   MOBILE WATER SUPPLY ALL                       1000 LBS

ž  AERIAL/QUINT/TOWER ALL               2500 LB

Firehouse Magazine May 2013

Apparatus Architect

By Mike Wilbur and Tom W Shand