Smith-Blair · Compression Coupling
Style 525 Compression Coupling
Galvanized Ductile or Malleable Iron, 1/2 to 2 in
150 PSI Max Working Pressure
-20°F to +180°F Temperature
Nitrile (Buna-N) Gasket
Galvanized Ductile or Malleable Iron Body
0.84-2.38 in Pipe OD
1-3.5 lb Weight
Description
The Smith-Blair Style 525 compression coupling is a ductile or malleable iron coupling with threaded ends that seal to the pipe as the compression nuts are turned. It stabs onto plain-end pipe of the same diameter from 1/2 to 2 in, with a galvanized finish for corrosion resistance.
A carbon steel retainer cup holds each gasket in place and concentrates compression where it is needed most, and the protected gasket's molded-in brass spring extends gasket life and gives electrical continuity between pipe and coupling. With Smith-Blair adapter gaskets it also joins copper tube.
Application: joining plain-end pipe of the same diameter in water, wastewater and industrial service, and replacing split or damaged pipe.
Key Features
- Working pressure up to 150 PSI
- Stab fit for easier installation
- Wrench flats on the nuts and sleeve hold the coupling while tightening
- Protected gasket with brass spring for longer life and electrical continuity
- Deflection up to 2° per end for pipe that is not perfectly aligned
What Ships and What It Needs to Run
Included: the coupling — sleeve, two compression nuts, retainers and protected Nitrile gaskets — ready to install.
Sold each. The price is per coupling; Smith-Blair packs them 12 to 24 per carton (see the table below).
Adapter gaskets for copper tube, ordered separately. Smith-Blair adapter gaskets let the 525 join copper tube; ask us to include them with the tube size.
Genuine Smith-Blair equipment, factory-new in original packaging — sold and supported by Watermain Supply, an independent industrial supplier.
12-Month Smith-Blair Warranty
Smith-Blair warrants its products to be free of defects in materials and workmanship for one year from the date of shipment by Smith-Blair. Dated proof of purchase, such as a bill of sale, is required to establish eligibility. Smith-Blair will repair or, at its option, replace a defective product; the product is returned to the factory or warehouse Smith-Blair designates.
Working Pressure
Up to 150 PSI on every size from 1/2 to 2 in; for a particular installation the allowable pressure also depends on pipe size and type, pipe condition, service conditions and installation workmanship.
Materials Specifications
| Sleeve |
Ductile or malleable iron, galvanized, with cast-in wrench flats |
| Gasket |
Nitrile (Buna-N) per ASTM D2000 with a brass helix spring molded into the leading edge; resists water, oil, acids, alkalies and most (aliphatic) hydrocarbons |
| Compression nut |
Ductile or malleable iron, galvanized, with cast-in wrench flats |
| Retainer |
Carbon steel, holds the gasket and concentrates sealing compression |
| Finish |
Galvanized |
Materials subject to change by the manufacturer.
Pipe Applications
Steel, stainless steel and PVC; copper tube with Smith-Blair adapter gaskets.
Sizes
| Pipe size and OD |
|---|
| 1/2 in - 0.84 in OD |
| 3/4 in - 1.05 in OD |
| 1 in - 1.32 in OD |
| 1-1/4 in - 1.66 in OD |
| 1-1/2 in - 1.90 in OD |
| 2 in - 2.38 in OD |
Choose the size in the first option; the part number shows in the last option.
Carton Quantities
| Nominal size |
Per carton |
Carton weight |
| 1/2 in |
24 |
24 lb |
| 3/4 in |
24 |
32 lb |
| 1 in |
16 |
24 lb |
| 1-1/4 in |
12 |
22 lb |
| 1-1/2 in |
12 |
33 lb |
| 2 in |
12 |
42 lb |
Couplings are sold each; full cartons on request.
Installation Notes
- Clean the pipe where the gaskets seat — to bare metal on protected-gasket couplings, for electrical continuity — and mark each pipe at least 3 in from the end to center the coupling.
- Loosen the compression nuts until the gaskets are free, and lubricate the pipe and gaskets with a soap-and-water solution that meets the water and pipe supplier's requirements.
- Stab the pipe ends in using the reference marks: each end at least 1/2 in past the gasket tip, with a 1/4 in gap between pipe ends recommended.
- Tighten by turning the nuts, never the sleeve, to the torque and wrench length in the instructions.
- For water, wastewater and industrial service: Smith-Blair does not recommend the 525 for natural gas.
- Anchor the pipe: the coupling seals around it, and Smith-Blair requires proper anchoring to restrain pipe movement and prevent pull-out.
From Smith-Blair Installation Instructions TI-013 (Rev 10/04/21), in the Data Sheet tab.
Before You OrderAll Smith-Blair products are Made to Order and Non-Returnable.
Items typically shipped in 5 - 10 business days.
Odd pipe ODs and other gasket materials are built to order — email sales@watermainsupply.com with the pipe OD and material.
