From time immemorial water has been the basic weapon of the Firefighter. From the Roman “squirt” devices to the modern engine driven pumps, applying water to a fire is the basic attack weapon and solution to fire.
Certainly water distribution systems in towns and cities have been around for over 175 years and in many cases simple hose streams from fire hydrants have been sufficient to combat fires. But in rural areas there are no or very limited water distribution systems and water must be either transported to the incident scene or provision made to utilise a static water source such as a pond or stream for additional volumes. Such additional sources, whether used to fill apparatus tanks for transport to a scene or for immediate firefighting employ a variety of hardware and operational methods.
Certainly there are numerous methods by which water is applied to a fire scene; these include sprays, solid streams, CAFS (Compressed Air Foam System), water/foam, high-pressure fog, at low and high pressures, and combinations thereof. But there is a common thread to all such uses which is a consistent and adequate water supply. There are all sorts of specialised hardware items, in addition to the simple fire nozzle, that are carried on fire appliances and the amount of water needed is dependent on the property on fire. In addition to the firefighting water there are also water requirements for dilution, wash downs, decontamination and other uses other than being applied on a fire. Hazardous Material operations alone require significant water supplies for a variety of needs and uses.
Most fire appliances carry an on-board supply of water which is used for an initial fire attack or other application. Even today, with the powerful engines and appliances available, the volume of this initial attack water is limited. In the USA a typical fire pumper will have a minimum capacity of 500 US gallons (1,900 litres) supply although this may increase to 1,500 US gallons (5,700 litres). Various other appliances, such as aerial devices, brush trucks, and tankers (sometimes called tenders) will have various size tanks and pumps dependent on local needs. While engines are powerful, there are weight restrictions on roads and bridges which is especially true in rural areas where access to a fire scene may involve substandard (weight limited) bridges, cattle gaps, narrow driveways and treacherous roadways.
The method of attack, as well as fire type and size, will also determine the efficacy of a small water supply with a larger supply obviously better suited for fire attack.
Of the 30,000+ fire departments in the USA, most are smaller rural departments that do not have the luxury of a hydrant-based or pressurised water supply. Likewise these departments are usually limited in manpower at the initial response with the time required to traverse the distances from a fire station to a rural location allowing a fire to grow significantly. Even if a small town has a domestic water supply it will be limited in flow, pressure and sustainability to adequately support fire flow demand and therefore water must be transported to an emergency scene by various types of tank equipped vehicles.
In addition to the need to provide the resources to safely combat a fire there is the aspect of insurance rates. Various insurance companies, standards making organisations and governmental regulatory bodies’ rate fire departments on the basis of the number and type of appliances, responding firefighter numbers and capabilities and adherence to National Standards such as those promulgated by the NFPA (National Fire Protection Association). The results of the rating significantly affect fire insurance rates and while there are several such rating methods in the different states, Mississippi has a privately run agency. The Mississippi State Fire Insurance Rating Bureau, which evaluates and rates fire departments and municipalities on a variety of Fire Protection capabilities. In addition to the fire department itself there are considerations given to fire codes, construction standards, water supply and/or transport capabilities, as well as personnel training and participation.
A Class 10 rating is the basic evaluation and requires a fire department to have a minimum 500 gallon/minute (1,500 litres/min) pump, an on-board water tank with a minimum capacity of minimum 500 US gallons (1,500 litres), a list of tools and equipment, a minimum hose supply and a minimum number of fire fighters attending each call. With increased capabilities such as a continuous water supply, career firefighters, fire codes, apparatus capabilities and a list of additional resources results in the Class Rating being reduced. A Class 1 rating is the best attainable with reductions in the Class Rating resulting in a reduction in insurance rates.
For a rural department to reduce the basic Class 10 Rating the provision of a better water supply is the basic criteria. If the Department can provide up to 15,000 gallons (57,000 litres) of water to a scene in one hour, a basic 250 gallons/minute (950 litres/min) a Class 9 may be achieved. If the total amount is 30,000 gallons (114,000 litres) the flow rate is increased to 500 gallons/minute (1,900 litres/min) a Class 8 will result.
There are several rules and guidelines regarding the supply of such water volumes, namely the number of vehicles involved, the distances from a fire station, the provision of a water supply to the scene, the number of personnel involved, basic hardware lists, etc. The reduction in fire insurance rates by reducing the rating from a Class 10 to a Class 8 may be as much as 30%. There are corresponding reductions in insurance rates for lower classifications but the 10 to 8 reduction sees the greatest percentage saving.
In most rural areas a tanker based water supply system is employed to provide adequate and reliable amounts of water to a scene. This water shuttle operation is pretty simple; the first arriving vehicle starts a fire attack using an on-board water supply and deploys a portable tank or dam. Other arriving water carrying vehicles dump their loads into this portable tank and then scurry off to refill their tanks for eventual return to the scene.
These portable tanks will vary in capacity from 1,000 gallons (3,800 litres) to 3,000 gallons (11,400 litres) and are sometimes ganged together. Suction hoses are employed to get the water from the portable tanks into the fire pump and high flows may be achieved dependent on the length and diameter of the suction hose used. The discharge flows from the fire pump are the usual configuration which achieve and the normal flows and pressures appropriate to firefighting.
Oktibbeha County, Mississippi is somewhat unique as the County Fire Departments utilise overhead water tanks for rural water supplies. These tanks are elevated, not pressurised and are usually located on a rural water system and located at strategic points. Such rural water systems simply do not have the flow or pressure capacity to support a fire flow operation although they are capable of filling an overhead tank, although it may take a few days to do so! These overhead tanks are equipped with alarms for low water level, visual indicators of how full the tank is and have thermostatically controlled heaters to handle sustained colder weather (yes, it does freeze in Mississippi!). The majority of these tanks were obtained as redundant gasoline tanks which were cleaned and mounted on reinforced supports as water weighs more than gasoline.
The tanks are equipped with 10 inch (254 mm) diameter discharge valves and the fire appliances have a 24 x 24 inch (600 x 600 mm) opening at the top of the vehicle tank. These openings have a spring loaded cover which deflects when water is poured from the top but closes if water tries to surge out of the opening due to vehicle movement. The vehicle tanks have a “dump” valve at the rear and/or side of the tank for discharging into the ground level portable tank at a scene. The refilling operation for a 3,500 gallon (13,300 litre) vehicle tank may be achieved using an overhead tank in less than 49 seconds, using one operator who does not even need to leave the ground. This operation is the equivalent of 2,858 gallon/min (10,861 litre/min) hydrant and there are no delays in hooking up and disconnecting supply hoses with the supply valve control being extremely rapid.
Other sources of water, such as ponds, ground level tanks, and streams are available all of which are accessed via dry-hydrants, portable and floating pumps and simple suction hoses.
An adequate and easily obtained water supply is the key to a successful firefighting operation. A little extra investment in hardware, plus some organisation and innovation, as well as the paperwork necessary to document such operations provides for less fire damage as well as providing better fire protection, enhanced firefighter safety as well as providing significantly reduced insurance rates.