Variable Spring Support

The Variable Support is a spring loaded device used for the support of piping and equipment where normal vertical movement is anticipated.

Variable Supports are manufactured in five different Travel Series which allow up to ten inches of movement and twenty-five different sizes allowing up to 50,000 pounds of load.
Seven different mounting Types allow the user the widest selection of configurations to accommodate practically every hanger design.

Spring Specifications

All spring units are designed to meet the requirements of:

  • ASME Code for Pressure Piping, ASME B31.1, B31.3
  • Manufacturers Standardization Society (MSS), SP-58,and SP-69
  • Federal Specification A-A-1192-A and WW-H-171-E

Recommended Service

Normally for support if Piping system where thermal changes cause the system dimensions and position to change and where load transfer to equipment is not a problem.

Maximum recommended variation from the operating load is 25%. A constant support should be used when variability exceeds 25%. Also used for support if equipment and ductwork to customer specifications.

Standard Specifications

  • Precompression – precompressing the spring coil into the hanger casing saves headroom by reducing the size of the casing, reduces the installed envelope size and also weight and erection time.
  • Closed-coil spring casing design protects the coil from damage and weather.
  • Steel Construction – spring, casing, and internal parts are fabricated of steel making them rugged and compact. All welding is done to the strict requirements of ASME Section IX.
  • The Piston Plate serves as a centering device and guide maintaining coil concentricity under normal operating conditions.
  • Load Indicators are visible in the slots and are clearly readable.
  • Stainless steel nameplate and travel scale are corrosion resistant.
  • All spring hangers are calibrated for accurate loading conditions.
  • The unit is preset at the factory to the Cold Load upon request.
  • For each series there is a reserve travel at the upper and lower limits of the working range of the spring.
  • Allowable spring coil stresses conform to ANSI/MSS-SP-58.
  • Standard finish is a quality rust resisting primer paint.
  • A turnbuckle or other suitable coupling is utilized for adjustment of rod type spring units. F type springs utilize an adjustable load column.
  • All F type units are supplied with a load flange.


  • Travel Stop – set at the Cold load position changes the spring into a rigid support for hydrostatic testing or other purposes. The strength of the Travel Stop is designed so that it can withstand (up to) 2 times the normal load.
  • Adjustable Travel Stop – allows the resetting of Preset/Travel Stop at any location within the normal operating range of the travel.
  • Limit Stops – permanently installed to prevent the movement of the pipe beyond a predetermined distance or load within the travel range of the spring.
  • Load Column Guide – for Type F units only, to prevent tipping of the Load Flange due to anticipated eccentric loading.
  • Extended Load Column – for Type F units only, thelength of the load column is furnished longer than normalper customer request.
  • Lifting Lugs – are available on larger sizes to facilitateerection and installation.
  • Hot-dip Galvanized Finish – available for protection against weather and corrosive conditions. The unit is galvanized to ASTM A-153 except the spring coil which is epoxy powder coated to assure protection to the coil as it flexes. The load column of the F Type spring is electrogalvanized. Maximum ambient temperature for the epoxy powdered coating is 350° F (177° C).
  • Epoxy Paint Finish – available for protection against weather and corrosive conditions. The unit is painted with a two-part zinc rich epoxy paint except the spring coil which is epoxy powder coated.
  • Stainless Steel Construction – allows the greatest degree of corrosion protection. Constructed completely of stainless steel except the spring coil which can be epoxy powder coated for economy.

Refer this Catalog for detailed specifications, sizing, load capacity :


When ordering a variable spring support please specify for each unit :

  1. Travel Series : 910,920,940,960 or 980
  2. Spring Type : A,B,C,D,E,F OR G
  3. Spring Size :  0 through 22 for all Travel Series; 000 and 00 available for Travel series 920 only.
  4. Movements and Direction of movement from the cold (Installed) position to the Hot (operating) position.
  5. Hot Load (Operating Position)
  6. Cold Load (Installed Position)
  7. Road Spacing : For Type G only, Specify center to center rod dimension.
  8. Customer Hanger Identification or Mark Number (if any).
  9. Finish : Primer Painted, Galvanized, Epoxy Painted, Stainless Steel or Special customer requirements.
  10. Type B and C units do not come with connections pins to the structure. If required, please order as a Figure 291 and specify pin size and finish.
  11. Specify if unit requires travel Stops, Lofting Lungs, Limit Stop Load Column Guide, Adjustable Travel stops or any other special feature desired.

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