Measuring the impact
A Fire Protection Research Foundation study helps evaluate fire-protection water usage.
Water used by fire protection systems is typically provided by a local purveyor. The local purveyor distributes water for use in residential, commercial and industrial buildings through delivery systems that usually include elevated gravity tanks, ground storage tanks and pumping systems, or a combination of both tanks. Water is provided to the end user for a fee charged by the local purveyor.
According to a U.S. Geological Survey based on data from 2005, an estimated 410 billion gallons of water were used per day in the United States. Of that, the leading users were thermo-electric power generation and irrigation. Public use was estimated at 44.2 billion gallons per day, or approximately 13% of all fresh water used in a day, and 21% of all freshwater used excluding thermo-electric power generation. The amount of public water use from 2000 to 2005 increased by 2%, while the population increased by more than 5%.
Water used for fire protection is a fraction of the overall public use of water, yet fire protection systems do have an impact on water use. A recent National Fire Protection Association Fire Protection Research Foundation study will help give water purveyors and others the means to evaluate water usage for fire protection, and it will provide perspective on the amount of water used for fire protection compared with other uses.
Fire water flow requirements for buildings in the United States are typically based on model codes and standards published by NFPA and International Code Council, as well as with guidance from the Insurance Services Office.
Actual water used for fire protection will differ due to many variables, including pressure, system design, fire department use and response time.
Over the past 30 years, selected municipal water authorities have implemented strategies, including standby fees and other policies to recover costs for water consumed in fires in sprinklered buildings. The fees also are used to fund maintenance of the distribution system, tanks, pumps and pipes necessary to get these higher-than-normal demands to the needed location.
Typically these fees are not directly related to sprinkler flows, but rather are in recognition of the fact these flows may not be metered and thus not accounted for in conventional water cost recovery mechanisms.
In contrast, water consumed at fires in unsprinklered properties is typically not subject to fees or metered at the hydrant. With the growing adoption of residential sprinkler ordinances in communities across the country, the Fire Protection Research Foundation conducted a project in 2011 to assess the relative community effects of water consumption in sprinklered and unsprinklered properties.
The study considered the water used in various building types with and without automatic sprinkler protection during a fire condition and estimated the water used per year for commissioning, inspection, testing and maintenance of buildings with systems for each building type.
The anticipated fire water usage was compared with the current fire water fees in six sample jurisdictions. The sample jurisdictions were selected based on populations, range of building types and fee structures. Surveys were conducted to determine the fee structure in each of the sample jurisdictions.
The study provides a detailed analysis for calculating the fire water demand required in sprinklered and unsprinklered buildings. The results show that in all scenarios studied, the calculated water used during a fire when a building has a sprinkler system is less than that of an unsprinklered building.
Additionally, the analysis indicates that in most of the scenarios studied, the fire water used during a fire in an unsprinklered building exceeds the total water used in an otherwise similar sprinklered building for both commissioning, inspection, testing and maintenance, and a fire condition.
These findings conclude that an owner of an unsprinklered building receives the full benefit of unlimited water through the public water system in a fire scenario without an increased cost, while the owner of a sprinklered building pays for the water used for commissioning, inspection, testing and maintenance, and a means that will reduce the amount of water required from a private water system during a fire condition.
In both cases, the cost of the water is typically not differentiated between sprinklered and unsprinklered buildings regardless of the reduction.