Aluminum 3" Female NPT to 2 1/2" Male NH

Item Number: 37R3N25
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  • Made In USA
  • Weight: 1.2 lb
  • Female Side: 3 inch NPT
  • The Female Will Only Connect to a Male 3 inch NPT
  • Male Side: 2 1/2 inch NH / NST
  • The Male Will Only Connect to a Female 2 1/2 inch NH / NST
  • Material: 6061-T6 Aluminum
  • Finish: Hard Coat Anodized
  • Complies With NFPA 1963 (Corrosion Resistance)
  • 99.95% Lead-Free

Description

This aluminum adapter is Made in the USA with 3 inch female NPT threads to 2 1/2 inch male NH threads. Crafted from seamless extruded 6061-T6 aluminum with a hard coat anodized finish per MIL-A-8625 Type III, Class 1, it offers resistance to corrosion and abrasion. This adapter features a 99.95% lead-free composition, complies with NFPA 1963 for corrosion resistance, and is suitable for fire safety and industrial applications requiring reliable connections. It has a maximum working pressure of 600 PSI and is hydrostatically tested to 1000 PSI.

Help Me Connect

  • The female side of a garden hose will only connect to a male garden hose connection
  • The male side of a garden hose will only connect to a female garden hose connection

NH / NST: The most common thread type in use by fire departments today is NST or National Standard Thread. NST also goes by the initials NH or National Hose. It can even be referred to as NHT or National Hose Thread but NST or NH is more common these days. NH = NST.

  • The female side of a NH / NST coupling will only connect to a male NH / NST connection
  • The male side of a NH / NST coupling will only connect to a female NH / NST connection

NPSH: National Pipe Straight Hose (NPSH) or Iron Pipe Thread (IPT) has the same threads per inch (TPI) as National Pipe Tapered (NPT) but the thread does not taper. NPSH is a straight thread and seals by a gasket in the female coupling which allows for a swivel, just like NH / NST, which make both ideal for hose couplings.

  • The female side of a NPSH coupling will only connect to a male NPT pipe or a male NPSH connection
  • The male side of a NPSH coupling will only connect to a female NPSH connection.
  • It will NOT thread into a female NPT pipe. For example, a male NPSH coupling will NOT thread into a female metal or pvc pipe.

NPT: National Pipe Tapered is common in plumbing and some industrial uses. Sometimes referred to as pipe thread because PVC pipe and schedule 40 pipe are typically threaded in NPT. As its name implies this is a tapered thread so that the outside diameter of the male (ODM) gets smaller towards the end of the fitting and the inside diameter of the female narrows with depth. As the two fittings are threaded together the opposite tapers force thread friction and makes the seal without the use of a gasket.

Warranty Information

Limited Lifetime Warranty - We will replace any adapters with manufacturer defects in material and workmanship. All warranty claims must be returned to us for inspection before we determine a solution.

Our warranty does not cover gaskets, multiple use of NPT threads, shipping cost, cosmetic damages, normal wear-and-tear, improper use or chemical damage.

Adapters purchased for use at Fire Training Facilities will have a 90-day Manufacturer Defect warranty only.

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Additional Details

Aluminum adapters are fabricated from seamless extruded 6061-T6 aluminum and hard coat anodized per MIL-A-8625 Type III, Class 1. Threads have a blunt start Higbee cut with indicators on adjacent lugs. Part identifications are permanent and stamped prior to hardcoat. Adapters and components meet the requirements of NFPA 1963.

The Safe Water Drinking Act section 1417 requires "Lead-Free" products to be a minimum of 99.75% lead-free.

Aluminum Female to Male Adapter

Specifications

Garden Hose Thread Male Adapter
  • Outside diameter of a male GHT adapter: 1 1/16 inches (1.06) - 11.5 Threads per inch
  • Garden hose thread is not the same as 3/4 inch pipe thread (NPT)
1" Male Adapter
  • Inside diameter of a male adapter: 1 inch
  • Outside diameter of a male NH / NST adapter: 1 3/8 inches (1.375) - 8 Threads per inch
  • Outside diameter a male NPSH or NPT adapter: 1 5/16 inches (1.295) - 11.5 Threads per inch
1 1/2" Male Adapter
  • Inside diameter of a male adapter: 1 1/2 inches
  • Outside diameter of a male NH / NST adapter: 2 inches (1.99) - 9 Threads per inch
  • Outside diameter a male NPSH or NPT adapter: 1 7/8 inches (1.87) - 11.5 Threads per inch
1 3/4" Hose Couplings
  • 1 3/4 inch hoses come with 1 1/2 inch couplings
2" Male Adapter
  • Inside diameter of a male adapter: 2 inches
  • Outside diameter of a male NH / NST adapter: 2 1/2 inches (2.51) - 8 Threads per inch
  • Outside diameter a male NPSH or NPT adapter: 2 3/8 inches (2.35) - 11.5 Threads per inch

Note: 2 inch NH or NST is very rare. If the outside diameter of male adapter is approximately two inches, you need 1 1/2 inch NH or NST.

2 1/2" Male Adapter
  • Inside diameter of a male adapter: 2 1/2 inches
  • Outside diameter of a male NH / NST adapter: 3 1/16 inches (3.06) - 7.5 Threads per inch
  • Outside diameter a male NPSH or NPT adapter: 2 7/8 inches (2.84) - 8 Threads per inch
3" Hose Couplings
  • Most 3 inch hoses come with 2 1/2 inch couplings
  • Inside diameter of a male adapter: 3 inches
  • Outside diameter of a male NH / NST adapter: 3 5/8 inches (3.62) - 6 Threads per inch
  • Outside diameter a male NPSH adapter: 3 1/2 inches (3.47) - 8 Threads per inch
  • Outside diameter a male NPT adapter: 3 3/8 inches (3.38) - 8 Threads per inch
4" Male Adapter
  • Inside diameter of a male adapter: 4 inches
  • Outside diameter of a male NH / NST adapter: 5 inches (5.01) - 4 Threads per inch
  • Outside diameter a male NPSH adapter: 4 1/2 inches (4.47) - 8 Threads per inch
4 1/2” Male Adapter
  • Inside diameter of a male adapter: 4 1/2 inches
  • Outside diameter of a male NH / NST adapter: 5 3/4 inches (5.76) - 4 Threads per inch
  • Outside diameter a male NPSH or NPT adapter: 5 inches (4.97) - 8 Threads per inch
5" Male Adapter
  • Inside diameter of a male adapter: 5 inches
  • Outside diameter of a male NH / NST adapter: 6 1/4 inches (6.26) - 4 Threads per inch
  • Outside diameter of a male NPSH adapter: 5 9/16 inches (5.56) - 8 Threads per inch
  • Outside diameter of a male NPT adapter: 5 7/16 inches (5.44) - 8 Threads per inch
6" Male Adapter
  • Inside diameter of a male adapter: 6 inches
  • Outside diameter of a male NH / NST adapter: 7 1/32 inches (7.025) - 4 Threads per inch
  • Outside diameter of a male NPSH adapter: 6 5/8 inches (6.62) - 8 Threads per inch
  • Outside diameter of a male NPT adapter: 6 1/2 inches (6.50) - 8 Threads per inch

FAQs

What are the thread specifications for this adapter?

This adapter features a 3 inch Female NPT (National Pipe Tapered) thread on one side, designed to connect to a male 3 inch NPT pipe. The other side has a 2 1/2 inch Male NH/NST (National Hose/National Standard Thread), which connects to a female 2 1/2 inch NH/NST coupling.

What material is used to construct this adapter?

The adapter is made from seamless extruded 6061-T6 aluminum. It features a hard coat anodized finish, adhering to MIL-A-8625 Type III, Class 1, which provides corrosion and abrasion resistance.

Is this product considered "Lead Free"?

Yes, this adapter is 99.95% lead-free, meeting the Safe Water Drinking Act section 1417 requirement for "Lead-Free" products, which specifies a minimum of 99.75% lead-free content.

What is the maximum working pressure for this adapter?

This adapter has a maximum working pressure of 600 PSI. It is designed to withstand a hydrostatic test of 1000 PSI, ensuring durability under pressure.

Does this adapter require a gasket for sealing?

The 2 1/2 inch Male NH/NST side of the adapter typically seals with an EPDM gasket. The 3 inch Female NPT side creates a seal through its tapered threads when connected to a male NPT pipe, generally not requiring a gasket.

What industry standards does this adapter comply with?

This adapter complies with NFPA 1963 for corrosion resistance. Its threads conform to specifications outlined in the Federal Handbook, USDA, NFPA, and UL, including a blunt start Higbee cut.

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