Elastomeric Expansion Joint Installation

Expansion Joint Design GuideGallagher recently released its Expansion Joint Design Guide, now available for download on our site.  This design guide takes an in-depth look at elastomeric, metal, and flue duct expansion joints.  The excerpt below is a section of our Expansion Joint Design Guide focusing on types of elastomeric joint installation, pipe layouts, and joint troubleshooting.  To download the entire guide, visit our Resources Page, or click on the image to the right.


Preparation

Expansion Joint InstallationCheck Service Range
  • Double check expansion joint performance limits against anticipated operating conditions
  • Check temperature, pressure, vacuum recommendations
  • Check total joint deflection—alter as needed to reduce deflection to correct range
  • Anchor lines
Check Location
  • Proper location is usually close to main anchoring point
  • Install pipe guide(s) for proper alignment
  • Joint should absorb pipeline expansion / contraction between fixed anchor points

Check Cover
  • Check outside joint cover for damage
  • Cover will keep harmful materials from penetrating joint carcass
Check Alignment
  • Alignment should be 0.125” (3.2 mm) or less
  • If 0.125” (3.2mm) must be exceeded, use a special offset joint
Check Support
  • Weight must not be carried by joint
  • Support with hangers or anchors
Check Flanges
  • Clean all mating flanges
  • Do not gouge or mutilate surfaces during cleaning
  • Carefully examine used parts for smoothness

Installation

Apply Lubricant
  • On elastomeric joints only, not required with all PTFE- or FEP-lined joints
  • Coat rubber faces with graphite in water, or glycerine, to prevent joint adherence to pipe flanges
Insert Bolts from Arch Side
  • On elastomeric joints only, not necessary with PTFE joints/couplings with threaded holes
  • Set bolt heads adjacent to arch
Tighten bolts
  • Elastomeric joints only, tighten gradually and equally, alternating around flange
  • Edges of joint must bulge slightly at flange O.D.
Check tightness
  • Within one week after application, then periodically
  • In hot or cold water systems during cyclical changes

Typical Piping Layout

Expansion Joint - Piping Setup
Pipe is anchored to support it and to stabilize the expansion joint. Pipe leg anchor should be used for horizontal suction piping, while an “H-Frame” should be used to anchor vertical discharge where end thrust causes lateral motion and potentially excessive misalignment.

Proper Use of Anchors in Branch Connections

Expasion Joint - Anchors in Branch Connections
Anchors should be bolted to floor and welded to pipe before installation of expansion joint.
All anchors and guides should be installed according to EJMA standards.

General Precautions for Elastomeric Joints

  • Use proper care breaking seal
  • Drive flanges apart gently with wooden wedges
  • Bring insulation only to pipe flange—do not insulate over or around joint
  • Covering joints may make leak detection difficult
  • Insulation could restrict joint movement or cause overheating
  • Store in cool, dry, dark area
  • Do not rest on flange edges
  • Carefully protect joints near welding operations
  • Never install spool-type joints next to flangeless check valves or butterfly valves
  • Install only against full-face metal flanges or damage/leakage could result; restrictions also apply to raised face or any non-full face flange

Troubleshooting

Expansion Joint - LeakageFlange Leakage
  • Check bolt tightness
  • Check mating flange surface area for:
    • Grooves
    • Scratches
    • Distorted areas
  • Over-extension may indicate need for control units
Liquid weeping from bolt holes
  • Check tube portion of joint for leaks; replace if necessary
Expansion Joint - CrackingCracking at base of arch or flange
  • Check installed face-to-face dimensions for over-extension or over-compression
  • Check for proper pipe alignment: must not exceed 0.125” (3.2mm)
Excessive ballooning of arch
  • Indicates distortion/deterioration of joint strengthening members, or excessive system pressure
  • Re-evaluate service conditions
  • Install new joint