Written by David Richardson, ER Customer and Administration Major at Midwest City Fire Department (OK)
This article will give an overview of ISO’s (Insurance Services Office) complicated “Deployment Analysis” within the Fire Suppression Rating Schedule (FSRS 2013), which is used for the evaluation of a community in relation to fire station locations. This article is for someone REALLY wanting to learn more about ISO’s methodology in how they credit fire stations. If that doesn’t spark your interest, then this will likely be a very “dry” read. For those that wish to continue on, it may require re-reading for it to sink in fully to comprehend the mechanisms and methodology used to determine “needed fire stations.”
First things first, ISO will no longer tell you where to build a fire station. Since 2013, they now only calculate how the existing station locations will affect your score, and from that analysis it may be determined that additional station locations are needed, but they won’t necessarily tell you “where.” Item #560 (pg.31) within ISO’s Field Suppression Rating Schedule (FSRS 2013) states, “The built-upon area of the fire protection area should have a first-due engine company within 1.5 road miles and a ladder-service company within 2.5 road miles.” This item is a heavy hitter and worth 10% of the entire fire department portion (which is 50% of the grading). The department must strive to have adequate fire station locations via a map study or demonstrated response times using NFPA 1710 standards. At a bare minimum, a fire station should be placed so that every part of the jurisdiction is within 5 miles of a fire station for even the most basic of credit with ISO (anything beyond 5 miles is considered class 10 or no recognized fire protection).
What exactly does this mean? For starters, one key phrase to remember is “road miles.” This means you can’t use “as the crow flies.” A 1.5-mile circle around a fire station does not suffice. A road may wind, a bridge may be too low or doesn’t meet the GVWR, or maybe a street dead-ends thus changing the route necessary, and this is why an “as the crow flies” analysis isn’t possible. Also, generally speaking, most communities already have a station(s), so evaluation of fire stations comes down to keeping a station in its current location, moving existing station(s) to a different location, or considering additional stations in areas of growth.
THE FRAMEWORK AND STRUCTURE
Let me explain ISO’s deployment analysis methodology a bit further. In 2012/2013 ISO updated the Fire Suppression Rating Schedule (FSRS). ISO began crediting Item #560 (Fire Station Locations) in one of two manners: 1) using the decades-old road mile/hydrant analysis, or 2) utilizing NFPA 1710 standards to show a demonstrated performance in relation to meeting the time constraints for an initial and full alarm assignment. This is where Emergency Reporting comes in to play in documenting and demonstrating that your department can provide adequate performance with existing station locations.
The nice part about this new method of analyzing and allowing NFPA 1710 performance is ISO will credit the better of the two methodologies for the engine and ladder separately! For instance, if the road mile/hydrant map study method for engine company locations scores the jurisdiction 45% effective (this would be a large area with few stations) but the NFPA 1710 times show 72% compliance (this means fire crews really hustled to get to the scene), then the ISO rep will use the better NFPA 1710 times for the engine company credit. The same holds true when evaluating the 2.5-mile ladder-service company, but if the NFPA 1710 times were better, then the ISO rep. has the freedom to apply that credit regardless of how the engine credit was determined. Emergency Reporting report #1722 or #1768 are good reports your department can use to measure your NFPA 1710 times specifically to NFIRS 111 (Structure fire) incidents.
The map above depicts a road mile analysis done by my GIS department for our city. The jurisdiction is 26.5 square miles with six stations. The light blue circles indicate a 1000′ diameter from the center of a hydrant. The red dotted line is the 2.5-mile ladder location (only one exists) and all other smaller squares are the 1.5-mile engine company locations (five in total). A 100% accurate map would not have perfectly straight diamonds, but would rather follow the roads for a rough diamond or irregular polygon. The above map analysis gives you a pretty good idea of a jurisdiction with rather good coverage! This particular road mile analysis concluded that 76% engine coverage exists (above and beyond the overlaps) and 41% ladder coverage is present. If you think about it, 1.5 miles in each direction from the center point (fire station) is 3 miles, and the ladder is going to be 5 miles. So, six stations can effectively cover quite a bit of ground!
Alternatively, below is Emergency Reporting #1722 (Incident Response and Apparatus Times with NFPA 1710 for Date Range for Incident Type for Zone for Apparatus for Response Mode) and if NFPA 1710 times (80-sec turnout, 4 min/8 min travel) are going to be used by the field rep, they are going to be looking at a few items: 1) Only structure fires in the last 12 months (NFIRS 111 incidents), 2) When the first engine arrived (within 320 seconds), 3) Did two engines and a ladder or service company arrive at all fire calls?, and 4) how long did it take the full complement of the additional units to arrive (560 seconds)? In the example below, the results were that the engine compliance was at 68% and ladder compliance was at 100%.
The chart below breaks down both NFPA 1221 and 1710 times.
If you are not familiar with NFPA 1710 times, this chart combines both NFPA 1221 (dispatch) and 1710 (fire department response) because essentially, they blend together to create a “total alarm time.”
The end result for our community in our most recent survey by ISO was that we were credited with a 76% engine coverage according to the road mile analysis, and 100% ladder coverage from the NFPA 1710 time analysis. Other factors such as the equipment carried also play into the formula and are not discussed here (my department had nearly 100% of equipment carried in our case), so the credit given to my fire department amounted to 8.46 out of 10 pts (84.60%).
Many paid departments may see better results using NFPA 1710 times while volunteer departments will likely see better results with the road mile analysis due to the delay a volunteer department usually has in responding.
The breakdown of determining engine companies by a road map analysis looks at existing fire engine locations and conducting a hydrant count. This is done by looking at each 1.5-mile boundary from the center of the station and going outward and counting the hydrants within that 1.5-mile polygon. The hydrants can only be counted once for each 1.5-mile boundary (should the boundaries overlap). After tallying up all the hydrants, simply divide that by the number of stations to get the average, then divide that average in half. That final number is now the number you use to analyze the map to see if any additional areas with that 50% hydrant count remains. If you find any areas with that 50% or greater number of hydrants, that means additional station locations are needed based upon the map study (not NFPA 1710 performance). So, if you only had 1 fire station with 2,000 hydrants within 1.5 miles and then if there are any other areas with 1,000 hydrants beyond the initial 2,000, those area(s) would require an additional needed location. Let’s use another example: if you have 3 stations then add up the total hydrants within 1.5 miles around each station (do not double count ANY hydrants if the 1.5-mile boundary overlaps), then divide by 3 to get the average, that average would be cut in half to determine the number of hydrants required beyond 1.5 miles for additional station locations. So, the simple math example would be station 1 has 300 hydrants, station 2 has 480 hydrants, and station 3 has 215 hydrants (3 stations with a grand total of 995 hydrants. Dividing those 995 hydrants by 3 stations gives you an average of 332). You take that hydrant average and divide by 2 and you get 166 hydrants. SO, if any areas within 5 miles of a fire station have 166 or more hydrants around them that means an additional fire station is needed in the eyes of ISO. If you are a hauled water/tanker shuttle jurisdiction, that study looks at 5-mile distances between each station and calculates travel time to fill site locations and hypothetical structures. You must prove that you can deliver 250 GPM for the duration of 2 hours within those 5 miles of the fire station(s). This type study includes a fixed 35 mph travel speed in relation to fill site locations and fire station locations, as well as dump and fill times.
The ladder/truck company analysis takes the same engine hydrant count method but does a couple of things differently. First, it uses a 2.5-mile boundary instead of 1.5 miles. The second is determining if there are five or more buildings within that 2.5 miles that meet the requirements of a ladder. The basic premise is to ask yourself: do you have 5 more buildings that are 35′ or taller OR have an NFF greater than 3500 GPM or any combination of those two requirements? If yes then plot those on a map. Then determine if those 5+ buildings are within the same 2.5 miles of a ladder company location. If yes then you probably need a ladder(s).
What if you know you need 1 ladder but are asking yourself, “how do I find out if I need more than 1 ladder?” That gets a bit more complicated. Assuming you have counted and plotted the “targeted” buildings within 2.5 miles without double counting any buildings or overlapping the 2.5-mile boundary for any additional areas, you now have to conduct the same hydrant count as what was done previously with the engine locations. This process simply involves counting all the hydrants within 2.5 miles of the ladder location(s). If you have a second (or third or fourth…) area on the map you have identified with 5 or more buildings over 35′ or over 3500gpm NFF (beyond the 2.5-mile boundary of any other potential locations) AND the hydrant count meets the 50% threshold in those additional areas (without double counting any hydrants) you need another ladder. So, if you have 3,000 hydrants within 2.5 miles of Ladder 1, then you need 50% or 1,500 hydrants around the potential ladder 2 area to meet ISO’s requirement of a second needed ladder company and 5+ buildings must be in that same area.
A great example of thinking ISO will require 2 ladder locations, but didn’t, is in my own community. We had 22 buildings that met the criteria previously mentioned within 2.5 miles of the existing location. A second location identified an additional 13 buildings, but when we applied the hydrant count to the equation the second location did not meet the 50% hydrant count that existed around fire station 1 and thus ISO only recognized the need for 1 ladder within our 26.5 square mile jurisdiction.
In the end, your organization may determine a ladder makes sense regardless of what ISO deems not needed. There is no point loss, it just doesn’t give you additional points for having it; so it is up to you to do what is best for your community. Remember that just because you have more than what ISO is requiring doesn’t mean you will get credit for it. The ISO Field Suppression Rating Schedule is a credit-based system starting at zero and goes up to 105.5. The system does not allow “over credit” on any component. I’ve heard all too often “I got dinged for this or marked off for that…”, but often the reality is you may have exceeded ISO’s requirements thus nothing was taken away, just simply no additional credit was given.
The following information was public information taken from ISO in 2017
“In evaluating a community’s public fire protection, ISO considers the distribution of fire companies. Generally, ISO’s criteria say that a built-upon area of a community should have a first-due engine company within 1.5 road miles of the protected properties and a ladder-service company within 2.5 road miles.
Those benchmark criteria produce an expected response time of 3.2 minutes for an engine company and 4.9 minutes for a ladder-service company, based on a formula developed by the RAND Corporation.
RAND conducted extensive studies of fire department response times. They concluded that the average speed for a fire apparatus responding with emergency lights and siren is 35 mph. That speed considers average terrain, average traffic, weather, and slowing down for intersections.
Taking into account the average speed and the time required for an apparatus to accelerate from a stop to the travel speed, RAND developed the following equation for calculating the travel time:
In our analysis of company distribution, ISO does not measure or use actual historical response times of individual communities. Many fire departments lack accurate and reliable response-time information, and there is no standardized national recordkeeping system that would allow us to determine accurate departmental response times.ISO, working with several fire departments, recently conducted its own review of the formula and found the earlier RAND work still valid as a predictive tool.
Also, it would be inappropriate to incite fire service personnel to push fire apparatus beyond a safe driving speed for the sake of faster response times, especially since U.S. Fire Administration statistics for 2005 indicate that 17 percent of firefighter on-duty fatalities resulted from responding to alarms.”
If you made it to this far, then you really must be interested in the mechanics of how ISO thinks in terms of crediting fire stations within their FSRS, so I applaud you! Not many take the time to understand the logic and reasoning of station location and many times it simply comes down to land available to build upon. The ISO evaluation was once a mysterious beast that scared many fire personnel and happened only once (maybe twice) in a career, but the reality today is they occur about every 4 years and it is a much faster-paced visit! Keep one thing in mind, the evaluation is taking a snapshot in time of literally hundreds of facts and figures on how well the jurisdiction will, can, or does respond to structure fires only.
About David Richardson
David is an Administration Major for the Midwest City Fire Department, a suburb of Oklahoma City, which proudly boasts an ISO Class 1 rating since 2006. Midwest City covers 26 sq. miles, has 6 stations, 90 staff members, & has 7000+ calls a year. David has been with Midwest City Fire Department since 2006 and is held accountable for a $12 million budget, records management, and serves as the public information officer.
Prior to joining the fire service, David joined ISO in 1999, where he managed competing interests and disparate stakeholders in the insurance industry pricing arena. David’s job was to gather data for Verisk (ISO Community Hazard Mitigation), which would in turn be used by the insurance industry to charge community policyholders accordingly. Generally, the community benefited from the ISO evaluation by thoroughly examining its communications, fire, & water systems. In simplest terms, David was an ISO Field Representative evaluating a community’s ability to provide fire protection.
Today, David combines his experience and utilizes the tools within ER to manage records and constantly strives to work towards streamlining input and output of data for the purpose of encompassing strategic planning and always being prepared for ISO.