Frequently Asked Questions

We aim to answer all your frequent questions, and will update this part of our website as we receive more questions. Hopefully you will find the answer you are looking for here.


The Novus Uniflon range is specially designed for strong acid and alkali applications

The Novus Uniflon range is a biaxially modified PTFE that gives additional resistance to creep and relaxation.

Lubricant lessens the friction value. This decreases the torque value during flange assembly. Lubricated bolts are easier to break out than non-lubricated bolts.

  • The yield of the bolts
  • Maximum stress of the gasket
  • Type of Lubricant used

Controlled methods of tightening are when calibrated equipment such as Hydraulic wrenches or hand torque wrenches are used. This ensures that bolted joints are running at peak performance and lessens the possibility of joint failures.

Generally, the best suited gasket for steam application is Spiral wound graphite gaskets.

The two most common type of gaskets used for Heat Exchangers is the Novus Kammprofile and the Novus MRG. MRG gasket is recommended for pressures less than 40 Bar. Kammprofile gaskets are recommended for high pressure and temperature applications.

Fibre gaskets contains rubber. The rubber hardens at elevated temperatures. When re-torqueing is done after a period in service, it is possible that the gasket will be crushed or crack due to the hardening of the rubber.

Materials are subjected to a wide range of tests as specified by statutory regulations and customer requirements. Approvals enable customers to make informed decisions as to the suitability of a product for a particular application.

Soft cut gaskets are suggested to be used on 150# and 300# pressure classes.

All Shims are quoted as a box of 10

The international standard for colour coding on spirals is ASME B16.20. Novus can also provide client specific colour coding if required.

  • Stud bolts and Nuts
  • Isolating sleeve
  • Isolating washer
  • Steel washer
  • Isolating gasket
  • Spark gap (Upon request)

Yes, All our gaskets are manufactured in our manufacturing facility in Brakpan.

A standard spiral wound gasket compresses from 4.5mm to between 3.2mm and 3.5mm.

Generally it is impracticable to replace fasteners every time a gasket is replaced due to cost implications. It is important to have history on the bolts that are used. Bolts can generally be re-used as long as the following checks have been done:

  1. Bolts were not tightened over the yield of the material
  2. There is no damage to the bolts.
  3. Bolts are not heavily corroded.

The spiral wound gasket style is dependent on the type of flange used. Style SGIR spiral wound gasket is suggested for Raised face and flat face flanges. Style RF1 spiral wound gasket is suggested for tongue and groove and groove to flat flanges. RFIR spiral wound gaskets is suggested for male to female flanges.

The inner ring of the spiral wound gasket prevents the winding from buckling when gasket stress is applied.

Design Temperature Design Media Design Pressure Type of Joint involved Criticality (Should the application be critical a double seal gasket could be used)

The flange rating determines the Flange / Gasket dimensions for standard size flanges. (i.e. ASME B16.5 - 150#, 300#, 600# etc, BS4504 – PN10, PN16, PN25, PN40, etc).

Ring - A circular gasket with no bolt holes, usually placed inside the bolt circle and typically used in raised face flanges Full Face - A gasket covering the entire flange surface and including bolt holes