Hose testing involves much labor and time. However, an innovative and inexpensive piece of equipment will permit safe quality hose testing at relatively high pressures in the field without the use of a pumper.
In these times of fiscal restraint, it's hard to justify starting up the apparatus to test one or two sections of repaired hose. Is it even cost efficient to test 10 sections?
A portable piece of equipment that any fire department can afford, and probably can manufacture, could prove to be a reliable, inexpensive device for testing hose.
If you plan to use the hose tester for 3-inch or larger hose, allow enough space betwen the tester's outlets so gloved hands and spanners can work easily. The bleeder valve can be fairly small (1/2-inch or 3/4-inch) since it's designed only to bleed off excess pressure when the test is through.
When determining the size of the water inlet, keep in mind that the smaller the inlet, the longer it takes to purge the hose of air and fill it with water, especially when testing larger diameter hose. Suggested inlet size is a 1/2-inch hose fitting where it can be hooked up to a hydrant with proper fittings for maximum water flow.
A gate valve with a constricted orifice should be installed at the base of the air chamber. To construct a constricted orifice, just drill a 3/16-inch hole in the gate, ball or check valve to limit the flow (volume) of air pushing on the water if a line ruptures. This will also reduce the danger of whipping hose.
When constructing the mounting stand, watch out for too much height. You want just enough room so the lugs of the coupling clear the ground. If the stand is too high it will rock. You may want to drill two or three 1/2-inch holes in the base of the test stand. This will enable you to drive 3/8-inch reinforcement rods shaped like a T through the holes to stabilize the test stand when charging the lines, and to limit the reaction force on the test stand if couplings blow.
On the wooden stand, mount a brass label plate designating the date of construction; the date of the hydrostatic testing and the date due for another hydrostatic test (depending upon your department schedule or when a part is repaired/replaced); and what psi rating the device was pressure tested to. This will enhance the safe operating life of the testing equipment.
After assembly, the device should be hydrostatically tested to 400 psi for at least 15 seconds and not more than one minute. This will ensure that the device is safe to operate at rated pressures for hose testing.
The air supply can be from any source: compressor, SCBA air cylinder or a 220-cubic-foot compressed air cylinder. The critical part is the regulator. It should be of the two-stage type with two gages and removable control key. This will ensure that once the test pressure is set, no one can accidentally change the setting. After the test is complete, always back off on the control key so tension is not kept on the diaphragm. If you cannot locate a regulator with a removable control key, try substituting an alien screw for the control key.
Let's review the hose testing procedures and the NFPA 1961 standards on fire hose and the 1962 standards on fire hose, care, maintenance and use. Keep in mind that these are minimum standards and that your department may exceed them.
There are two major tests given to fire hose. The first is the acceptance test given to all new hose by the manufacturer. The second test is the service test that the end user, the fire department, gives the hose.
The date and psi pressure rating (usually 400 or 600 psi) of the manufacturer's acceptance test is marked on the hose jacket. Be sure to ask whether the hose was tested with or without couplings. Some fire departments install couplings on hose themselves, and then it is up to them to conduct the acceptance test. Also included in the acceptance test are the burst test, maximum burst pressure of the hose; the kink test, to check the strength of the jackets when kinked; the elongation test, to check if the hose elongates or stresses excessively; the twist test, to check if the hose twists excessively and to be sure the final twist is always clockwise to tighten the coupling; the warp test, to check that the hose does not move left or right more than 20 inches per 50 feet; and the rise test, to make sure the hose does not rise off the ground when both ends are held rigidly to the test table.
These acceptance tests vary for single-jacket, multiple-jacket, cotton, synthetic and relay hose. If in doubt, check the NFPA 1961 standards.
The service test procedures are covered in the NFPA 1962 standards. Briefly stated, the test method involves using a 300-foot maximum hose length to ensure that all air is removed. Each line being tested should have a restricted orifice, and couplings should be marked to check slippages (see diagram 2).
We are now ready to pressurize the fire hose. Although 250 psi is the standard, pressure can vary according to the type and size of the hose being tested, e.g., relay suction. The minimum time to maintain the test pressure is five minutes. During this time, personnel should walk the length of the hose to check for leaks, using extreme caution during inspection and remembering not to straddle the hose and to keep at least 15 feet to the left side. (The left side is determined by looking down the hose from the testing point (see diagram 3). This procedure is done because if the hose ruptures, its free end will usually whip to the right.
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