The XYZ Fire Department recently bought a new pumper. The apparatus committee took great care to make sure the new rig met the National Fire Protection Association 1901 standard, but when the Insurance Services Office rated the pumper, the department lost points. Everyone looked at each other and asked, "What happened?"

The answer is simple. NFPA 1901 and ISO have different requirements for apparatus, and departments need to understand those differences when they write the specifications.

Different focus, different standards
Most of the differences between NFPA and ISO exist because the two organizations have different focuses on apparatus.

NFPA focuses broadly on the safety and performance of apparatus. Changes to the NFPA standard only require consensus approval of a committee, and the standard is usually revised every three to five years. Although NFPA standards are generally not law, they can affect a department's liability.

ISO focuses specifically on the fire suppression capabilities of apparatus. Changes to the ISO rating system require approval of insurance regulatory agencies in every affected state, and the system is rarely revised. Although ISO ratings do not directly affect departments, they do affect fire insurance premiums for property owners in each department's response area.

The net result is that NFPA apparatus requirements now differ from ISO rating requirements for overall apparatus configurations, as well as for specific equipment. The differences are most significant for pumpers and aerials.

Pumpers
The minimum required ISO pump capacity depends on several factors including building construction, distance between buildings and the number and pump capacities of other pumpers responding. Departments in areas where the number, size and separation distance of buildings is changing dramatically should discuss pump capacity requirements with an ISO representative.

Differences between NFPA and ISO requirements for pumper equipment include hose, monitors, ground ladders, foam and radios.

For example, NFPA 1901 requires that each structure pumper carry a minimum of 800 feet of 2½-inch or larger supply hose. ISO requires 1,200 feet of 2½-inch or larger supply hose, or a combination of 800 feet of 2½-inch or larger supply hose plus 400 feet of 2-, 2½- or 3-inch attack hose.

NFPA 1901 has no requirement for booster hose. ISO requires 200 feet of booster hose or an additional 200 feet of pre-connected 1½- or 1¾-inch hose.

NFPA 1901 has no requirement for a monitor or heavy stream appliance. ISO requires a 1,000gpm or larger monitor if the Basic Fire Flow is 1,500gpm or more. The Basic Fire Flow is calculated based on several factors and is best discussed with an ISO representative.

NFPA 1901 requires an extension, roof and attic ladder of any length. ISO requires a minimum of a 24-foot extension and 12-foot roof ladder, but has no rating requirement for an attic ladder.

NFPA 1901 has no requirements for foam nozzles or foam concentrate on structure pumpers. ISO requires a foam nozzle, eductor, proportioner or compressed air foam system, plus 10 gallons of foam concentrate. ISO also wants an additional 15 gallons of foam concentrate either spare or carried on the apparatus.

And finally, NFPA 1901 has no requirements for radios on pumpers, while ISO requires both a mounted and a portable radio.

ISO assigns the most points for the monitor (if required), radios and hose, as well as for annual pump testing. Departments can review all the pumper equipment requirements and assigned rating points here.

Aerials
The minimum required ISO aerial length depends on the height and set-back of buildings within a response area. The maximum required aerial length is 100 feet but ISO will pro-rate ratings for aerials with insufficient length. The aerial should have the capability to deliver an elevated master stream. Water towers will not receive credit as an aerial, but will get credit for an elevated master stream.

Differences between NFPA and ISO requirements for aerial equipment include SCBA, ground ladders and radios. Aerials also need to carry a variety of service company equipment such as a generator, lights, saws and salvage covers.

NFPA 1901 requires one SCBA and one spare air bottle for every assigned seating position with a minimum of four SCBA and spare bottles. ISO requires a minimum of six SCBA and spare bottles, no matter how many seating positions are assigned.

NFPA 1901 requires a minimum of 85 feet of ground ladders of any length on a quint and a minimum of 115 feet on an aerial. ISO requires a minimum of 150 to 159 feet of ground ladders on either a quint or an aerial to get full credit. ISO also has specific requirements for the type and length of each ground ladder.

And just as on pumpers, NFPA 1901 has no requirements for radios, while ISO requires both a mounted and a portable radio.

ISO assigns the most points for the aerial length, elevated master stream and radios. Departments can review all the aerial equipment requirements and assigned rating points here. They can review all the service company equipment requirements and assigned rating points here.

Look before you leap
The best advice for departments in the process of specifying new apparatus is to consider both NFPA 1901 and the ISO rating requirements. Each organization has its own requirements, and each is important. Understanding those requirements is the best way to maximize the value of your new apparatus purchase.