Series 3500 External Pressure Bellows Expansion Joints

Series 3500 External Pressure Bellows Expansion Joints

Information at a Glance


3500 External Pressure Bellows Expansion Joints




2″-240″ (50-6000)


≤150 & 300 (10 & 20)


16+” (400)

Canadian Registration


This product is registered throughout Canada under
CRN 0D9278.59870YTNADD3

Other Products

Product Description

Series 3500 Externally Pressurized Expansion Joints are designed for installations where the principal movement is axial. Standard single and dual designs are available 2” through 24” NPS with 4” through 16” axial compression. Service conditions are 150 and 300 psig to 500°F. Welded and flanged end connections are standard, with grooved ends optional.

Standard in-line pressure balanced configurations are available 2” through 24” NPS with 4”, 6” & 8” axial travel rated for 150 & 300 psig to 500°F.

The bellows element of Series 3500 Expansion Joints is completely enclosed and externally pressurized whichprevents damage to the bellows and eliminates pressure instability. The pipe telescopes into the expansion joint protecting the bellows and providing a smooth full bore interior. Series 3500 products are available from stock and have a Five year full replacement warranty.


Type 3502 Cut-a-way

Technology & Advantages

Series 3500 IS In-line Seismic Expansion Joints combine the axial motion capability and safety of Series 3500 Externally Pressurized Expansions with the universal motion capability and reliability of Hyspan Barco Ball Joints to provide in-line axial and lateral movements of +/- 6”, +/- 12”, +/-18” or +/- 24”.  This rugged reliable product provides seismic isolation of piping without a change in direction or the addition of pipe length.

Series Products


Alternative Products

Series 1500 Laminated Bellows Expansion Joints are comparable products that are available for steel pipe systems 2” through 14” with 2” or 3” travel.

Series 8500 Expansion Compensators are comparable products that are available in smaller diameters. Steel pipe and copper tube configurations
available with travels of 2” or 3”.

Series 9500 Alignment Guides are used adjacent to Series 3500 expansion joints and as intermediate guides throughout pipe and tube runs. Standard configurations 3/4″ through 14″ nominal pipe and copper tube sizes are available.

Ordering Information

  • Refer to Tables 5 through 10 to select the configuration and service conditions required for your application.
  • If the travel required is unknown, see the method of calculation on Page 5 (of the full catalog).

Single Expansion Joint Steel pipe weld ends 150 psig at 500°F maximum 4.0″ axial travel maximum 2″ NPS


3502: Type specification, steel pipe weld end both ends, steel housing and guides
131: Size & pressure designation, 2″ NPS, 150 PSIG
4: Axial travel, 4.0″ compression, 1.0″ extension

  • Single expansion joints, 3501 and 3502, ordered with anchor based are identified as 3501AB and 3502AB.
  • Anchor bases are standard on dual anchor base joints, 3505 and 3506, and do not require the AB suffix.
  • In-line pressure balanced joints are available as single configurations and identified as 3501PB and 3502PB—refer to In-Line Pressure Balanced Expansion Joints.

Hyspan products are available from Sales Representatives and Distributors, or they can be purchased direct from the factory. The minimum factory order for open account customers, COD shipments, or bank card sales is $100.00 (USD). All major credit or debit cards are accepted. The minimum order for new account applicants is $100.00. Our Confidential Credit Application can be downloaded and forwarded to Hyspan for processing. All orders are subject to the following Terms and Conditions, and the above warranty applies to all material. Please read these documents.

Terms and Conditions

Confidential Credit Application (13.9 KB), can be completed on line.