Frequently Asked Questions


1.0 Can the plugs be used as a permanent stopper in pipes?

HFT Pipestoppers® Aluminium Test Plugs can be used effectively as a permanent stopper. The wings can be cropped to prevent tampering.

2.0 Will HFT Pipestoppers® Aluminium Drain Test Plugs withstand attacks from various acids, alkalis and chemicals.

Technical data sheets about the chemical resistance of different materials is available on request.

3.0 What if HFT Pipestoppers® natural rubber rings deteriorate in the presence of my special chemicals, gases or fluids?

Synthetic sealing rings are available, made from nitrile, neoprene, silicone and viton rubbers which will resist attack by many harmful products.

4.0 What is the maximum working temperature for the HFT Pipestoppers® Aluminium Test Plugs and Stoppers?

The natural rubber rings can be used up to 70˚C (158˚F) in continuous use.

For higher temperatures, we manufacture rings made from silicone that can be used up to 300˚C (572˚F) and viton, which can be used up to 350˚C (662˚F).

Technical data sheets about the resistance of various rubbers to all temperatures and materials are available on request.

5.0 I have a hole to seal, where your plug won't quite seal well enough, but the next size up is too big. Do you have any in between sizes?

The user can extend the range of each plug by a few millimetres by using an exterior rubber seal on top of the ring provided.

More details are available on request.

6.0 Can I have the plugs made as a branded product?

Yes, we can supply the screw caps in your own house colours as well as black or white. Caps can be provided with your name, initials or logo printed on them.

7.0 What pressures can the plugs withstand?

A pressure chart for HFT Pipestoppers® Aluminium Testing Plugs is shown on the leaflet. (See the Downloads tab.)

Plugs can be braced to assist in greater stability.


Note: For effective sealing, internal surfaces of cavities must be clean and dry.

Pressure ratings may be affected by poor, slippery or dirty surfaces.

Some smooth surfaces may not be effective and may need to be roughened.


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