System Arrangement

DOE-STD-1066-99

such that the domestic and process systems can be isolated without shutting off the

fire system supply.

6.2

System Arrangement

6.2.1

Facilities having a Maximum Possible Fire Loss (MPFL) in excess of $100 million and

significant nuclear facilities (Catagory 1 Hazard) should be provided with an

additional, independent source of fire protection water.

6.2.2

Whenever feasible, all water distribution systems should be of the looped grid type

providing two-way flow with sectional valving arranged to provide alternate water flow

paths to any point in the system. In addition, sectional control valves should be

provided to limit the number of hydrants and individual sprinkler systems made

inoperative during a single line break to a total of five. Dead end runs utilized as a

single supply to fire hydrants should not exceed 300 feet.

6.2.3

Listed and/or approved control valves should be installed at maximum intervals of not

more than 5,000 feet on long supply lines and at maximum intervals of not more than

1200 feet on main distribution loops, feeders and all primary branches connected to

these lines. Such control valves should also be installed at selected points throughout

the distribution system to provide system control over each service area. At

intersections of distribution mains, one less control valve than the total number of

intersecting mains may be provided. As an aid in determining the minimum number

of sectional control valves, the critical nature of the building/facility should be

considered as well as the number of fire and domestic systems affected in a potential

line failure.

6.2.4

Sprinkler system water supply lead-ins should not run under buildings except for the

minimum distance possible. Sprinkler system risers and alarm valves should be

located as close as practical to a building entry point. Where a riser would otherwise

be located in a potentially contaminated area, consideration should be given to

locating the riser exterior to the building in a heated enclosure.

6.2.5

Hydrants should be provided so that hose runs from hydrants to all exterior portions

of a protected building are no more than 300 feet. Hydrants should not be closer to

than 40 feet to buildings.

7. AUTOMATIC SPRINKLER SYSTEM CRITERIA

7.1

NFPA Standard 13 should be used to determine the occupancy classification for any facility.

For facilities where there is a potential for a change in occupancy, light hazard occupancy

sprinkler system design criteria should not be used.

7.2

Hydraulically designed sprinkler systems should be designed for a supply pressure of at least

10% but not less than 10 psi below the supply curve. (Refer to NFPA Standard 13.)