Hot Bolt and Odd Bolting
These are methods often carried out in preparation for shutdown work. A permit must be issued for this work and risk assessments are required. It also must be carried out by experienced personnel and monitored constantly under controlled conditions following the procedures that are in place.
Stringent checks by the supervisor or senior engineers should be carried out to assess the practicality of using these procedures.
If in doubt, 3t Training Services can be consulted about a procedure and any risks that may be involved.
Hot Bolting
This is when only one bolt at a time is removed and replaced with a new bolt straight away. The bolt has been checked for the material specification and lubricated if required. The operating pressures should be reduced to a minimum to enable the work to be carried out in the safest manner possible.
Odd Bolting
This is when every other bolt is removed, leaving only 50% of the bolts remaining. This is carried out when the systems are shutting down, once the system is at a nominal pressure.
Restrictions on Hot and Odd Bolting
- Not to be carried out on flanges with less than 8 bolts.
- Systems carrying potentially toxic substances.
- Compact or Clamp Type connectors, Non standard flanges.
- Flanges with Insulating Gaskets or special applications.
- Risers or bellows systems.
The operation must be carried out under strictly controlled conditions.