By Bill Adams

Apparatus specifications (specs) published by fire departments, manufacturers, vendors, and consultants regularly refer to National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, as they should. Some refer to a Class A pumper (Class A), which they shouldn’t.

A few refer to the Insurance Services Office (ISO), which could result in a longer lasting financial impact on a community than using NFPA 1901 and Class A. Spec writers should understand the significance using each term may or may not have. There should be justifiable reasoning when references are included in a spec.

The intent of this article is not to split hairs over specification verbiage. The objective is to make purchasers aware that referencing the ISO and NFPA 1901 can have financial implications as well as operational consequences. Class A, on the other hand, is an ambiguous traditional term that has no formal definition. Its historical meaning is subject to multiple interpretations. Consequently, it doesn’t belong in a specification.

The ISO’s requirements have changed (for those jurisdictions that subscribe to them), and NFPA 1901’s are about to. Spec writers should be cognizant of those changes.


According to the ISO’s Web site, “ISO evaluates municipal fire-protection efforts in communities throughout the United States.” It analyzes efforts, grades them, and assigns a rating to them, which underwriters use to set insurance rates. The ISO states it is an “advisory organization” and “insurers may use our information, modify it, or not use it as they see fit.” Compliance is voluntary. Noncompliance may detrimentally affect a community’s rating and ultimately the cost of insurance within it.

One ISO tool used to grade fire protection is the Fire Suppression Rating Schedule (FSRS). It evaluates three major criteria: fire department, emergency communications, and water supply. There are substantial changes to the 2012 FSRS, including a new section designated “Community Risk Reduction.” Fire departments should understand the grading system, what is expected of them, and how they will be evaluated. I only address ISO changes to ancillary equipment carried on apparatus herein. It is a very small part of the grading process.

NFPA 1901

NFPA 1901 is a minimum standard for fire apparatus. I describe it as an unenforceable nationally recognized safety standard. The fear of legal action resulting from noncompliance influences voluntary adherence by manufacturers and end users. NFPA 1901’s newest revision is due in 2016. It is unlikely a manufacturer will deliver a noncompliant rig unless it receives a sign-off from the purchaser per NFPA 1901 Sentence Whether fire departments actually equip and operate apparatus per NFPA 1901 after delivery is questionable. I pass no judgment on that important local decision. Refer to NFPA 1901 Section 4.21 regarding responsibility. Be mindful-the definition of responsibility can encompass accountability and liability.

The authority having jurisdiction (AHJ) or a political subdivision at a local or state level may have legislation mandating NFPA 1901 and ISO compliance. The fire department, or even a professional association representing department members, may have contractual agreements requiring similar compliance. Understanding ISO and NFPA criteria and concurrent changes will benefit all parties. Exercise caution. Changes in NFPA 1901 and ISO requirements may place a financial burden on a community. There are no NFPA or ISO police, but there are tort lawyers.

Class A Pumpers

There is no formal description for Class A pumpers. NFPA 1901 does not address them nor does the ISO. But, purchasing specifications reference them on a daily basis. What do purchasers expect when they specify one? Most manufacturers certify that they build them. To illustrate, most specs include a statement similar to, “These specifications are for a Class A Pumper in compliance with the National Fire Protection Association NFPA 1901, Standard for Automotive Fire Apparatus, edition in effect at date of the bid opening.” In the verbiage describing the fire pump, another common statement is, “The fire pump shall be a Class A type.”

Many purchasing specifications include “yes” and “no” columns on each page where bidders are required to indicate compliance or noncompliance with each item. It’s an accepted practice in the industry. Bidders always check off “yes” for the two aforementioned sentences. Fire departments are publishing requirements they can’t define, compare, or evaluate. Astonishingly, manufacturers propose to supply apparatus that has no formal definition. NFPA 1901 Chapter 5 describes pumper fire apparatus, and Chapter 6 describes initial attack fire apparatus. NFPA 1901 and the ISO do not define or require Class A pumpers. Leave Class A out of purchasing specifications.

1938 Type 75, 750-gpm Class B Mack pumper
1 The former Engine 5, of the East Greenwich (RI) Fire District, is a 1938 Type 75, 750-gpm Class B Mack pumper. [Photo by Chief Jim Smith (Ret.), City of Warwick (RI) Fire Department.]

A and B History

The National Board of Fire Underwriters (NBFU) was the ISO’s forerunner. The International Association of Fire Engineers (IAFE) became the International Association of Fire Chiefs (IAFC). Gene Mahoney’s book, Introduction to Fire Apparatus and Equipment, provides insight into Class A terminology. It says that, around the early 1930s, the NBFU and the IAFE developed standards for a Class B pumper that delivered 100 percent capacity at 120-pound-per-square-inch (psi) discharge pressure, half capacity at 200 psi, and 1⁄3 capacity at 250 psi. It’s unknown why it was called Class B.

It states that during the 1940s, “national authorities” were contemplating a Class A pumper to deliver capacity at 150-psi discharge pressure, 70 percent at 200 psi, and half capacity at 250 psi-which is the basic requirement for today’s pumpers. It explains that the NBFU published “Suggested Specifications for Motor Fire Apparatus” in 1947 describing both Class A and B pumpers. Both were available until 1956, when the NBFU no longer recognized Class B. According to NFPA 1901’s Annex E, that organization addressed pumping apparatus in 1906 and started promulgating fire apparatus specifications in 1914, but I find no reference to Class A.

Whether the NFPA, NBFU, ISO, IAFC, or IAFE coined Class A is irrelevant. Class B is no more, and Class A is not defined anywhere. Class A is a generic term similar to a “triple combination pumper.” Everyone knows the intent, but there are no formal definitions. Neither belongs in purchasing specifications.

Today is not the first time generic, vague, or even regional terms have been used in apparatus specifications. In the mid 1800s, three steam engine manufacturers had their own specs with definitions of 1st class through 5th class engines. One New Jersey builder defined class by weight (horses had to pull them); one in Ohio defined class on the size of the piston; and one in New York based class solely on its capacity in gallons per minute (gpm). If a fire department on the West Coast wrote a purchasing spec for a 2nd class steamer, one wonders what it expected to receive.

Ancillary Equipment and Specs

Occasionally written in specs is, “The apparatus shall be ISO-compliant.” Seldom explained by vendors is that some equipment required by NFPA 1901 differs from the ISO. Some variations are significant. However, variations may be a moot point in the future. It was not unheard of for a fire department to purchase an NFPA-compliant apparatus and during a later ISO evaluation not receive 100 percent credit for the rig because it was not ISO-compliant. Oops.

Using ground ladders on a ladder truck as an example, NFPA 1901 only requires one folding, two extension, and two roof ladders totaling at least 115 feet. The ISO is precise in requiring the collapsible (folding) ladder, four extensions, and two roof ladders of certain sizes. The ISO allows specific equivalent equipment in some instances. Be advised that the 2012 FSRS cuts the required number of extension and roof ladders in half. On pumpers, NFPA 1901 does not state specific sizes for an extension and roof ladder, whereas ISO does.

Purchasers, be aware that times are changing. It appears the 2012 ISO no longer specifies the exact amount of ancillary equipment required. The ISO’s Community Fire Protection News Web site has an article titled, “ISO’s Fire Suppression Rating Schedule: Reinvented and Revised.” It states that fire apparatus “must meet at a minimum the general criteria of NFPA 1901.” I interpret that statement to include the required ancillary equipment. In my opinion, the terminology “general criteria” may be construed differently by each reader and possibly by the local ISO office. That is significant and concerning.

Apparatus may have to carry more equipment than before to meet ISO requirements. The 2012 FSRS Appendix A, Table 512A-Pumper Equipment and Hose, lists “some” of the equipment needed and the points credited for carrying it. There appear to be differences between it and the NFPA’s equipment list. Which one counts, and who decides?

There is no intention, insinuation, or condoning of a fire department gaming the system when writing specifications for a new rig. As previously mentioned, whether a department carries everything required by NFPA 1901 and the ISO is a local matter. Use care when writing specifications. Apparatus have to be designed to store equipment specified-whether the equipment is identified by individual name or by reference to a regulatory standard.


NFPA 1901 is very specific in describing ancillary equipment. I believe the ISO’s references to following the NFPA’s equipment lists can be confusing. There’s the possibility NFPA 1901’s use of the words “should,” “shall,” and “ought to” in describing equipment requirements may be construed differently by individual ISO evaluators. Does “meeting at a minimum the general criteria of NFPA 1901” include equipment the NFPA says you shall carry, you should carry, or you ought to consider carrying?

Read ISO and NFPA requirements very carefully. Formal opinions may be advisable. Firefighting is a job. A fire truck is a tool defined by NFPA 1901 to accomplish the job. The ISO grades how well that tool is equipped to accomplish the job. Good luck.

BILL ADAMS is a former fire apparatus salesman and a past chief of the East Rochester (NY) Fire Department. He has 50 years of experience in the volunteer fire service.

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