This process may require two to three hours.
Fire pump packing drip rate.
When adjusting pump packing the goal is to arrive at the lowest acceptable leak rate while maintaining thermal equilibrium.
Packing that is adjusted too loose can allow air to be sucked in through the packing during priming reducing the height that the pump can be primed at.
Overtightening is the most common cause of packing failure.
At the beginning of the pump operation loosen the gland nuts and allow the packing boxes to leak liberally.
The 60 drips per minute is a little more forgiving than the 5 drips per minute but should still be used as a limit for a maximum drip rate to be allowed.
Chapter 4 fire pumps 89 program for individual systems suction piping shall be fl ushed at a fl ow rate not less than indicated in table 14 1 1 1 a exhibit 4 1 and table 14 1 1 1 b exhibit 4 2 of nfpa 14 2010 or at.
Break tanks are most commonly used 1 as a means of backflow prevention between the water supply source and the fire pump suction pipe 2 to eliminate fluctuations in the water supply source pressure 3 to provide a stable and relatively constant suction pressure at the fire pump and or 4 to provide water storage to augment a water source that cannot provide the maximum flow rate.
For most braided pump packing liquid leakage is absolutely necessary to provide lubrication and cooling of the sealing surface and ensure the seal s long life.
The 60 drips per minute is a little more forgiving than the five drips per minute but should still be used as a limit for a maximum drip rate to be allowed.
But as the pump and packing start to set in you can expect a couple years of consistent and reliable service.
Two stage pumps in volume.
Packing that is adjusted too loose can allow air to be sucked in through the packing during priming reducing the height that at which the pump can be primed.
The correct drip rate for a packed pump is 10 120 drips per minute at 150 psi discharge pressure.
Every 20 minutes tighten the packing gland nuts one flat at a time until the leakage has been reduced to about 60 drops per minute.