Adequate ingress and egress are necessary to allow safe and rapid passage of both fire equipment and private vehicles in opposite directions simultaneously. But they can be costly not only in the expense of road construction but also in the resulting reduction of saleable lots because they require space. This is particularly true in lot-splitting situations where the original parcel can be divided only into four or less new parcels, thereby reducing the opportunity to spread costs. Adequate access is a cost that must be borne, however, if past disasters are not to be repeated time and again (Alger 1971, Los Angeles County Fire Dep. 1970, Orange County Bd. Sup. 1976, Oreg. St. Dep. For. 1978b, County Sup. Assoc. Calif. 1966, San Bernardino County Bd. Sup. 1974).
Proposed Standards: Meet all of the following standards; deny any variances that do not show positively that they will not adversely affect firefighting and evacuation capabilities:
The amount of water reserved for firefighting purposes and the size and type of delivery system provided depend on (a) the degree of wildfire hazard involved (fire hazard severity classification); and (b) the type and location of the occupancy (home or mobile home in a subdivision; farm or other individually developed homesite; multiple such as commercial, recreational, industrial, apartments, etc.). The water requirements for multiple occupancies are usually stipulated by the insurance carrier or local fire department or both. Although normally based on requirements for fighting an interior fire, they are usually adequate for protecting the building from an encroaching wildland fire as well, because usually these requirements are set quite high to reflect both the financial property risk and the multiple life risk.
Adequate water for firefighting purposes, either by a fire department or by the occupant, has been unavailable and unreliable on many occasions where homes were involved. In some cases, adequate water was available but not developed, as the potential fire problem was not recognized. In other situations the problem was recognized but considered a remote possibility. Sometimes the cost was considered too high. Sometimes a sufficient water supply was not available at any price-and in such a situation, the structure should not have been built. A common cause of water deficiency is the practice of extending or adding on to a subdivision where the water system was adequate for the original development and is adequate for domestic service to the addition but is insufficient to provide fire flows both to the original and to the additional developments. 3g (Alger 1971, Los Angeles County Fire Dep. 1970, Orange County Bd. Sup. 1976, County Sup. Assoc. Calif. 1966).
In contrast to normal daily use, consumption of water for firefighting purposes is of relatively short duration but of high volume. Water is also used during emergency conditions when electric power service may well be interrupted. Different engineering, therefore, is required than would be needed for a purely domestic water system. Water supplies for firefighting involve large storage facilities, high-volume mains, and dependable delivery (either gravity or pumps with alternate standby power sources). These facilities should be provided during the development phase as their price skyrockets if they must be added after development and occupancy (Orange County Bd. Sup. 1976, Oreg. St. Dep. For. 1978b, County Sup. Assoc. Calif. 1966, Nat]. Fire Prot. Assoc. 1974).
Proposed Standards: Adhere to the following standards as they apply to individual projects, and do not permit variances because they would expose both life and property to unacceptable risks:
Hazard class: Hydrant spacing Minimum flow (ft) (gal/min) Moderate 700 500 High 500 750 Extreme 300 1000
The greatest distance to which vegetative treatment is required by any existing law is 100 feet from the structure. Perimeter treatment around subdivisions and other high value areas (e.g., mobile home parks, recreation areas, shopping centers) should be at least to fuelbreak standards (200 feet minimum). And it should embody certain additional features for two reasons: (a) Vegetative and structural fuels must be physical] y separated by enough distance to reduce to an acceptable level the danger of ignition of structures by direct flame impingement or radiation-an even greater clearance (usually impractical if not impossible) would be necessary to protect against windborne firebrands; (b) firefighters must have a place in which to fight the fire before it reaches the structures, and so it is necessary to incorporate features which allow access by the firefighters and their equipment to the treated area (Los Angeles County Fire Dep. 1970, Orange County Bd. Sup. 1976, County Sup. Assoc. Calif. 1966, Green 1977).
This dual need can be met in several ways and many
combinations thereof. Probably the best means from the
firefighter's standpoint is a perimeter street with structures on the inside and a fuelbreak or greenbelt on the
outside. Usually this design is economically feasible
only if the adjacent area is to be subsequently subdivided. In certain topographic situations, such a design
is impossible (Orange County Bd. Sup. 1976).
Another way to achieve perimeter protection is to
construct a fuelbreak or greenbelt behind the outside
structures (fig. 5).
Fuelbreaks are strips of land in which the volume of vegetative fuel is reduced to an acceptable level and maintained in that condition. Greenbelts are similar strips of land wherein not only is the volume of native vegetation greatly reduced but much or all of it is replaced with irrigated introduced species. Strip parks and golf courses, are examples of greenbelts. They perform multiple functions (i.e., fire protection, recreation, esthetic benefits) and can often be made to pay for themselves (Los Angeles County 1973, Green 1977).
Although practical in economic and sometimes physical terms, fuelbreaks or greenbelts present some problems. Access to the treated area by firefighters is denied unless fire access easements are provided and dedicated to such use. These easements should be wide enough and of low enough gradient to allow access by motorized fire equipment as well as by personnel (Orange County Bd. Sup. 1976, County Sup. Assoc. Calif. 1966).
Other developments which can serve the purpose of perimeter fire protection, at least for limited pieces of the perimeter, are recreation areas (particularly waterbased ones), parking lots, school yards, and baseball or other athletic fields. With such developments placed on the perimeter the amount of otherwise unproductive fuelbreak and easements needed would be reduced3h (Alger 1971).
Proposed Standards: Include reduction of native vegetative fuels to at least fuelbreak standards as part of perimeter fire protection for subdivisions and mobile home parks. Provide access lanes to the treated area at least 12 feet wide for firefighting manpower and ground equipment at intervals not to exceed one-quarter mile. Base the minimum width of the treated strip on fire hazard severity classification: moderate-200 feet, high-300 feet, extreme-400 feet. Dedicate such treated areas and access lanes to public use and provide for their maintenance in perpetuity.
Distribution circuits accounted for nearly 17 percent of the conflagrations studied (Task Force on California's Wildland Fire Probl. 1972). This proportion was exceeded only by arson and was equalled by machine use. All other fire causes were smaller in number. Distribution circuits are of two types: primary and secondary. Primary circuits bring the power from the substation to the user's transformer. Primary electric power distribution circuits are a serious cause of wildland conflagrations. The thousands of miles of these lines present a tremendous exposure and an almost insurmountable problem of inspection and maintenance. Secondary circuits, which convey power from the transformer to the point of use (e.g., home, pump), usually cause fires because of inadequate vegetative clearance which is not now regulated by any State or local law. Secondary circuits cause nearly one fire for every two caused by primary distribution lines (Calif. Div. For. 1972, Moore 1977).
In about the lower half of their voltage range (i.e., 2.4 to 17 kilovolts), primary distribution circuits can successfully be installed underground rather than overhead. In the foreseeable future, even higher voltage lines can be installed underground. The subdivision codes of many cities now require such installation in all new subdivisions, although usually for visual esthetic reasons. The same requirement could be imposed in rural and wildland areas for fire protection reasons. Such a requirement would eliminate both primary and secondary circuits as sources of vegetation fires since the transformers would be at ground level or below. From this location the secondary circuit (service drop) is almost always placed underground also (Governor's Study Comm. Conflagrations 1966, Task Force on California's Wildland Fire Probl. 1972, Moore 1977).
If for some reason (e.g., excessive rock, preexisting overhead service) the cost of underground installation cannot be justified in relation to fire safety benefits, the developer should arrange for and the permitting agencies require very high standards of construction, vegetative clearance, inspection and maintenance of overhead power lines (Governor's Study Comm. 1966, Oreg. St. Dep. For. 1978a, County Sup. Assoc. Calif. 1966, Task Force on California's Wildland Fire Probl. 1972, Moore 1977). Proposed Standards:
Fire hazard Secondary Primary severity class: distribution distribution 0-750 volts 2.4-17KV 18-35KV Moderate 2 4 6 High 4 6 8 Extreme 6 8 10
Positive identification of location is not merely convenient to a firefighter or other public safety officer responding to a reported emergency or radioing for help; it is an absolute necessity. Developers or others assigning and posting names and numbers can greatly assist in providing adequate fire protection if they will make the signs as permanent as possible and large enough and with enough color contrast and reflective character to be read easily from a moving vehicle at night as well as in the daytime 3i (Oreg. St. Dep. For. 1978a, Oreg. St. Dep. For. 1978b, Task Force on California's Wildland Fire Probl. 1972, Colo. St. For. Serv. 1977).
Proposed Standards: Construct signs of nonflammable materials, with letters at least 3 inches high, halfinch line width, and a reflective color that contrasts sharply with the background of both the sign itself and the surrounding vegetation.
Proposed Standards: Dedicate fire station sites when: