Rerates and Derates

Why use Metalmark Engineering for your rerate or derate?

Speed in Proving Viability: We quickly determine if your pressure vessel or heat exchanger is a good candidate for a rerate*. 

Calculation Accuracy: We are experienced in using the latest software tools to generate the ASME Code calculations required for rerates and derates. 

Cost Savings: New pressure vessels and heat exchangers are expensive. Constructing a new vessel may not be necessary if another vessel can be rerated to meet your production needs.

Lead Time: Most new pressure vessels and heat exchangers take months to complete from design to installation. Rerated vessels may be used right away.

Process Experience: We are experienced in identifying API 571 damage mechanisms in process equipment and we understand the types of damage that may necessitate a derate.  

Reasons for a pressure vessel or heat exchanger rerate:

Increased production: To increase output, it might be necessary to operate the vessel or heat exchanger at a higher pressure or temperature than the original Maximum Allowable Working Pressure (MAWP).

Process changes: Process evolution may require equipment to be reused in a new process, requiring a different Maximum Allowable Working Pressure (MAWP) for the pressure vessel or heat exchanger than the original design.

Corrosion consideration: Original design calculations may not have considered corrosion and process realities may require a rerate to adequately consider observed process corrosion.

Fitness-for-service assessment: An inspection might reveal that the vessel or heat exchanger has reduced integrity due to local damage, necessitating a reduction in the Maximum Allowable Working Pressure (MAWP).

*Metalmark Engineering PLLC does not consider rerates that require a hydrotest to be good candidates. Most rerates do not require a hydrotest.