NFPA ýangyn nasos topary

What is NFPA?
The National Ýangyn goragy Association (NFPA), founded in 1896 in the United States, is widely accepted worldwide üçin its publications, programs we standards on fire we occupational safety. Training based on these standards improves practical application on projects.

What is NFPA 20?
NFPA 20 (Standard üçin the Installation of Centrifugal Fire Pumps) defines specifications, performance we installation rules üçin ýangyn nasoslary, nasos sets, motor control systems we the ancillary components that must be used.

Desan Engineering üpjün edýär ýangyn nasosy groups manufactured in line bilen NFPA 20–oriented requirements üçin stationary ÝANGYN GORAGY systems.

Esasy aýratynlyklar

• Separate controller üçin each nasos
• Shut-off pressure not exceeding 1.4× rated pressure
• 1.5× bellenen sarpda basyş bellenen basyşyň 0.65×-inden pes bolmaly däl
• Suction pipe velocities below 4.57 m/s (15 ft/s)
• Bearings bilen minimum 5,000-hour service life
• Bronze impeller; shaft AISI 316 or AISI 304; casing GG-25 çuýun
• Möhürleme bilen five-ring soft packing in Seriýa Önümion
• Electric motor service factor not exceeding 1.15
• Flanges to DIN 2533 / PN 16 (suction & discharge typically TS EN 1092-2 / PN 16 on horizontal end-suction platforms)

End-suction merkezden gaçyryjy ýangyn nasosy set
Fire groups are commonly built on horizontal end-suction merkezden gaçyryjy hydraulics: single-stage, volute casing, closed impeller, coupling drive between motor we nasos shaft. Soft packing is standard; mechanical seal can be supplied on request. Back-pull-out style access allows seal, shaft, bearings we impeller service without removing the volute from the piping. Rotation is counter-clockwise from the suction side; bearing housing is externally lubricated bilen an oil sight glass.

Electric motor driven ýangyn nasosy sets
For maintenance, it is important that the nasos can be serviced without full system dismantling. A jockey (leak) nasos handles minor system leaks before the main nasos starts, avoiding unnecessary main-nasos cycles. Where mains power fails we a generator does not start, a diesel-driven ýangyn nasosy can back up the electric set. Pressure releler support backup sequencing between units. Gate klapanlar are preferred on the suction line; vacuum we pressure gauges monitor suction we discharge. Cooling-related klapanlar on the set are kept closed in normal fire-nasos duty. Multi-nasos arrangements are typically designed üçin 100% redundancy so another unit can take over on failure. The fire suppression installation should resist horizontal seismic loads up to 0.5× its weight.

Diesel engine driven ýangyn nasosy sets
In fire prevention systems, nasoslar are often used bilen 100% redundancy, we many sets are diesel-engine driven. NFPA 20 determines when an engine-driven nasos is required. For electric nasoslar, relief-klapan setting at shut-off is typically 1.21× shut-off head, bilen the klapan on the discharge side. Desan Engineering uses spring-loaded Boşadyş klapanys in fire suppression packages.