Variable Spring Supports Webinar Q&A

The following questions were raised during the live webinar and are answered by Binder technical specialists. Responses are provided to support project engineers and specifiers by explaining typical spring support behaviour, applicable standards, and common industry practices.

1) Do base-type springs produce much of a frictional reaction on the pipe support and is this affected by clearances in the guided load column?

For base-mounted variable spring supports (Types F, H and K), the spring unit itself is designed to carry vertical load only and to permit vertical movement due to thermal expansion.

Any frictional reaction is therefore not generated by the spring mechanism, but by sliding between the pipe (or pipe shoe) and the support surface as the pipe moves.

For this reason, it is common industry practice for Binder base-mounted spring supports to be supplied with a PTFE sliding plate (typically PTFE on stainless steel) at the load flange interface. The purpose of this plate is to:

• minimise frictional resistance to axial pipe movement,
• reduce horizontal loads transferred into the piping system,
• improve repeatability of vertical spring movement.

2) How would I safely remove a spring support that is in service?

The Binder Installation, Operation and Maintenance Manuals address this in Sections 12 and 13.

Download Manuals from this page.

Key points include:

• Stored energy is present in the spring coil; uncontrolled release can cause serious injury and damage
• Removal generally follows the installation sequence outlined in the Binder Installation, Operation and Maintenance Manual
• For supports without Multilock™, Binder assumes the line has returned close to the pre-set (blue marker) position before any attempt is made to re-insert the pre-set stops
• Temporary pipe support or bracing is mandatory and is the responsibility of the person performing the removal
• For Multilock™ supports, the pressure plate can be locked at any position within the travel range, allowing safer removal even if the line cannot return to cold

3) Re the MSS-SP 58 recommendation for a limit of 25 percent on the range of load from cold to hot: is this driven by an intention to reduce load change on the piping system?

Yes. This limit is fundamentally about limiting the change in reaction load on the piping system as the pipe moves from cold to hot.

Variable spring supports change supporting force with travel, and the difference between hot and cold load acts as a changing reaction force on the pipe.

Standards such as MSS-SP 58 commonly limit spring load variability to 25 percent of the operating load. Where this limit cannot be achieved with a variable spring, common industry practice is to consider a constant spring support.

4) Is the bolted type connection of a spring hanger in a vibrating line such as a compressor inlet and outlet advisable, and can Binder spring supports handle this vibration?

Variable spring supports are designed to support weight and accommodate thermal movement. They are not intended to control vibration.

A bolted spring support may be used on a vibrating line, provided vibration control is addressed separately through piping design and restraint measures such as guides, struts, snubbers, or other vibration control devices.

Bolt detailing must follow good vibration practice, including appropriate locking, preload, and fatigue considerations. This is outside the scope of Binder’s guidance and must be determined by a qualified engineer.

5) Does Binder have software that can build or organise the assembly of different components depending on the requirement? Some spring vendors provide something like that.

No. Binder does not use a configurator or assembly-builder software for spring supports.

Binder’s process is based on a formal request or data form. When this information is properly completed, Binder can assess available product options and advise on an appropriate support type, size, and travel range based on the information supplied.

6) Can the hot load be the sustained load when piping is not in operation?

Yes. If the pipe remains in the operating (displaced) position when not in service, the operating or hot load can be the sustained load.

Spring supports can be supplied set to the operating load where the pipe cannot return to its original installed position, or where operating conditions govern the long-term load state.

If spring supports are required to be supplied pre-set to the operating load, this information needs to be provided to Binder at the time of quoting.

Spring supports may also be installed while the line is in operation, in which case the pressure plate position is checked against the operating (red) marker rather than the pre-set position.

Engineering implication:

• The sustained load condition is defined by the pipe’s long-term position, not whether the plant is running or shut down
• If the pipe remains hot, displaced, or restrained from returning, the operating load becomes the sustained load
• If the pipe cools and returns, the sustained load reverts to the pre-set (cold) condition

7) With all the engineering evident with these spring units, why was the larger unit selected in the worked example in the presentation? Isn’t that unnecessary over-engineering that simply provides more revenue for Binder?

Binder’s selection criteria is based on the client-provided design load and movement requirements, and on the available spring travel ranges (BV35, BV70, BV140, BV210) with defined working limits.

Full travel may be used where the piping system can tolerate the resulting load variation.

Common industry reasons for selecting a larger unit include:

• locating the required movement more centrally within the available travel range,
• reducing sensitivity to installation tolerances,
• improving compliance with load-variation limits,
• allowing margin for future system changes.