Increase your water Supply Options
WATER SUPPLIES
Photo courtesy of Granby Fire Department
Lowering a community’s ISO (Insurance Services Office) rating isn’t always easy, especially when you consider that additional deficiency points can be charged if a district has a good fire department but an inadequate water supply.
Yet, the town of Granby, MA, a rural/suburban community whose fire department depends solely on tanker shuttles to supply water from static sources, was able to reduce its Class 9 rating to a Class 7 by making low-cost modifications to the department’s present apparatus and by actually improving the amount and locations of the district’s water supplies.
One of the principle basis for the grading schedule’s evaluation of fire protection is the fire department’s ability to provide the needed fire flow;* and the minimum recognized water supply for grading purposes is 250 gpm delivered within five minutes of the arrival of the first-due apparatus and sustained for a two-hour period.
* The insurance grading schedule, which provides a yardstick for classifying a municipality’s fire defenses and physical conditions, covers four main areas: water supply; fire department equipment and operations: fire service communications; and fire safety control, including fire prevention and building regulations.
The 250-gpm fire flow had to be from sources certified by a registered professional engineer to contain a minimum of 30,000 pumpable gallons, which is the “minimum storage available during a drought with an average 50-year frequency.” It was obvious to all of us that many of our water locations were questionable and seasonal.
Lacking the necessary expertise and knowledge of ground water supplies, I contacted the Hampshire Conservation District for assistance. They provided technical assistance in developing a fire pond location inventory. We surveyed the entire town (28 square miles) in an effort to place a water location within one mile of all residences. Using annual rainfalls, drainage areas, and sub-soil samples, Soil Conservationist Pat Scanlon from the Soil Conservation Service of the U.S. Department of Agriculture completed the survey obtaining a list of 28 water locations that would be certifiable.
Public hearings and meetings were held with the town’s Conservation Commission and property owners were notified. Excavation and construction of the water sites were done during September and October, the driest time of the year. It was best to complete the excavation in one day, since most locations filled to capacity within 24 hours.
The smallest water location measures 50 X 50 X 8 feet deep with 2:1 side slopes (for every two feet you go horizontally, you must go one foot deeper) and is certified for 30,000 pumpable gallons. The largest is an existing lake certified at 32-million pumpable gallons. We also used certifiable streams and some of our neighboring towns’ hydrants as water locations. It was estimated that the top 24 inches of water would be lost to evaporation or ice, and the bottom 24 inches would not be pumpable due to weed growth and/or silt.
We also compiled a list of those water locations whose access roads may require snow removal. Our town’s Highway Department provides this service. Keep in mind that when developing a water location, allow for multiple pumper access so that multiple/quicker tanker filling is possible. Fencing was installed around some water supply locations for public safety as well as to keep livestock from eroding the slopes. Guardrails were installed where needed to prevent accidental entry by motor vehicles, and banks were seeded to deter erosion.
A yearly inspection and measurement survey is performed immediately after spring runoffs. This survey allows for a periodic cleaning and maintenance program to be carried out, guaranteeing pumpable gallonage throughout the year.
Although it was apparent that our fire suppression capabilities would be improved with these new water supplies, we wanted to justify the expense of the surveys and construction and also show the town administration the cost effectiveness of improving the fire department’s equipment.
Photos courtesy of Granby Fire Department
It was not possible to accumulate all the values of the town’s different structures or the many insurance variables that one might find on these buildings. So, to obtain a reasonably accurate savings that these improvements would net the town, several local insurance agents provided us with an average savings of 15% on residential properties. This indicated a $38 savings on the town’s average residential insurance premium. The $38 times the 1,389 homes that would be affected brought an impressive $52,782 savings. The savings that would also be available to the business community, to tax exempt properties, and to the town’s own buildings was not added to this figure due to the time and the complexities involved in doing so. With these statistics to back up our request for $32,000 to make the department’s changes and modifications, the funds were unanimously approved at the Town Meeting.
Fire department apparatus improvements consisted of installing 10-inch dump valves and two 1/4turn gated inlets on each of the three tankers. Quarter-turn hose couplings are used on all tanker inlets and fill lines. On a round trip of more than two miles, our three tankers delivered a total flow of 478 gpm minus 10% (to allow for spillage, underfilling, and incomplete unloading) for an actual flow of 435 gpm. The first-due response to structure fires outside the hydrant districts carries 7,000 gallons of water. Using ISO’s five-minute set-up time and the 250 gpm flow requirement, a 33minute time lapse can occur before tankers must begin cycling.
These improvements in water supplies yielded both a better ISO rating and an economic savings to the town of Granby. They also, along with apparatus equipment modifications, gave the fire department a more effective means of fighting fires and protecting the community.
For those areas where a tanker operation is not feasible, water supply was increased by experimenting with innovative methods of relay and drafting procedures. The following evolution was developed and adopted by the Granby Fire Department: Two hydraulic hose reels, each with the capacity to hold 2,000 feet of 3-inch hose, were installed on the existing hose trucks. Engine-1 carries 1,200 feet of 3-inch supply line. If a 5,000foot supply line is used, then Engine-1 and the hose truck operate as relay pumpers. Standard operating procedures call for the relay apparatus to be activated within 15 minutes.
At an actual incident, Brush-3, a 750-gpm pumper, responds directly to the water location and sets up a draft. R-2, the hose truck, responds directly to the water location and lays its 3-inch supply line from the brush truck toward the fire scene. Hose laying speed is 10 mph.
When the first reel of 2,000 feet of supply is empty, a hose clamp is applied 15-20 feet back from the hose fitting, and the second reel of 2,000 feet of 3-inch hose is connected and layed down.
At the end of the second 2,000 feet, the hose is then connected to the hose truck’s 500-gpm pump. It is necessary to clamp the supply line at the first 2,000 feet, as the line is being filled and layed down simultaneously. This clamp also indicates the location for Engine-1 to relay pump.
During the hose laying, Engine1 responds to the fire scene, quickly dumps its 1,000 gallons into a holding tank, attaches its 3-inch supply line to the fire scene engine, and reverse lays to the hose truck’s location, finishing 5,000 feet of supply line. Engine-1 then continues along the supply line until it reaches the clamp at the end of the first 2,000 feet of 3-inch hose. This is where Engine-1 begins relay pumping. Relay pumpers discharge the air in the line through an open discharge port before pumping into the next relay pumper (the hose truck). This way, only the air trapped in the last 1,000 feet of hose reaches the fire scene engine.
A delivery of 435 gpm was maintained over 5,000 feet of 3-inch hose.
Practically, this evolution is possible. However, if one were to calculate, on paper, the pressure and volume using classical hydraulic formulas and constants, the evolution is theoretically impossible to perform. When questioned, field representatives from the ISO in Parsippany, NJ, stated that it is not uncommon to find great discrepancies in formula results and actual field test results. The newer fabrics and linings used in the manufacture of hose today are almost making the standard hydraulic calculations inaccurate.
