NFPA 291 HYDRANT FLOW TESTING - mwua.orgmwua.org/wp-content/uploads/2018/05/NFPA-291-HYDRANT-FLOW-TESTING.pdf · A hydrant test requires three measurements: static pressure, esidual

NFPA 291 HYDRANT FLOW TESTING

Fire Flow Testing and Marking of Hydrants

4.2 Procedure

• Tests should be made during period of ordinary demand.

• One hydrant, designated the RESIDUAL hydrant, is chosen to be the hydrant where the normal static pressure will be observed with the other hydrants in the group closed, and where the residual pressure will be observed with the other hydrants flowing.

FIGURE 4.3.4

SECTION 4.3.6

• To obtain satisfactory test results of theoretical calculation of expected flows or rated capacities, sufficient discharge should be achieved to cause a drop in pressure at the residual hydrant of at least 25 percent, or to flow the total demand necessary for fire-fighting purposes.

4.5 Test Procedure

4.6 Pitot Readings

TABLE 4.10.1(a)

TWO HYDRANT FLOW TEST WITH A CALIBRATED FLOW DEVICE

HOSE FRICTION LOSS

WATER DATA WORKSHEET

WATER DATA WORKSHEET 2

HYDRANT TESTING PITFALLS

• WATER GUAGES NOT CALIBRATED

• INSUFFICIENT PRESSURE DROP ON RESIDUAL HYDRANT

• ELEVATION DIFFERENTIAL BETWEEN TEST AND RESIDUAL HYDRANT NOT RECORDED

• HYDRANT BUTT TYPE NOT DETERMINED

• HYDRANT TEST WORK SHEET INCOMPLETE

QUESTIONS