Smith-Blair Pipe Repair Dismantling Joint | Expansion Joint

Smith-Blair expansion joints and dismantling joints are engineered to solve the two most challenging installation problems in municipal and industrial piping systems: accommodating thermal pipe movement without stress fractures, and enabling field-installed adjustments when as-built conditions don't match the design spool length. These are precision-manufactured products that require correct specification to perform as designed — and the consequences of the wrong product or wrong length are costly.

As an authorized Smith-Blair distributor, Watermain Supply sources the full expansion joint and dismantling joint catalog including restrained, non-restrained, and rod-restrained configurations. Contact us with your pipe size, material, and travel requirement — we'll get you the right spec and a lead time.

Expansion Joints — Styles 611 & 612

Smith-Blair expansion joints absorb thermal expansion and contraction in rigid piping systems — pump stations, above-ground transmission mains, industrial process piping, and treatment plant piping where temperature differentials create repeated axial stress. They are designed to provide 10 inches of bi-directional travel and can be furnished with limit rods to prevent over-extension during pressure surges or system upsets.

• Style 611 – Expansion Joint, Single End, 10" Expansion — one telescoping end; used where thermal movement occurs primarily in one direction from a fixed anchor point; available with or without limit rods
• Style 612 – Expansion Joint, Double End, 10" Expansion — telescoping ends on both sides of a center spool; provides 10" of travel on each end (20" total system accommodation); for long unanchored pipe runs or pump station discharge piping; available with or without limit rods

Expansion joints require thrust restraint at adjacent anchors — they are not self-restraining. Limit rod configurations (Smith-Blair styles with "-LR" suffix) include steel limit rods that prevent over-extension under pressure surge or water hammer. Specify limit rods on all pump discharge applications and wherever pressure class exceeds 150 PSI.

Dismantling Joints — Styles 971, 972, 973, 975

Dismantling joints are used at valves, pumps, meters, and check valves where the designer anticipates future removal, replacement, or inspection of that component. A dismantling joint provides a few inches of telescoping adjustment that allows the flanged spool to be disassembled and re-engaged without cutting, grinding, or temporary bypass piping. Without a dismantling joint at a critical valve, removing it in the future requires cutting adjacent pipe — an expensive and disruptive operation on a live system.

• Style 971 – Non-Restrained Dismantling Joint — for low-pressure or gravity systems where external thrust restraint is provided by pipe system or concrete blocking; lowest cost configuration
• Style 972 – Heavy Duty Restrained Dismantling Joint — integral restraint engages the pipe OD to resist thrust without external blocking; the standard specification product for pump stations and pressurized systems; available in sizes 4" through 48"
• Style 973 – Restrained Dismantling Joint — restrained with rod-based restraint system; suitable for buried or partially-exposed installations where compact geometry is required
• Style 975 – Restrained Dismantling Joint — heavy-duty restrained configuration for large-diameter or high-pressure applications; specify system pressure and pipe OD at time of order

Design & Specification Guidance

Both expansion joints and dismantling joints are typically project-specific products with long lead times — standard stock is limited. To avoid project delays, provide the following information as early as possible: pipe material and OD, nominal pipe size, flange drilling standard (ANSI 125/150 or 250/300 lb), working pressure and test pressure, required travel range (expansion joints), and restrained vs. non-restrained specification.

Watermain Supply can coordinate directly with Smith-Blair engineering on non-standard configurations, project submittals, and material certifications. Contact us early in the design phase to confirm lead time before it becomes a project schedule issue.

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Call: 281.664.8000  |  Email: sales@watermainsupply.com