understanding heat exchangers

Industrial Heat Exchangers

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Heat Exchangers, Pressure Vessels, Fittings and CRNs???

Understanding heat exchangers can be somewhat complicated, understanding whether a heat exchanger

requires a CRN can be more complicated. Providing a definitive guide to access whether any heat exchanger

requires a CRN is impossible, however, general guidelines can be developed to assist designers and owners of

heat exchangers to assess whether they may require a CRN. We are providing this document for information

purposes only. Pressure Vessel Registration and Fitting Registration in Ontario are too complex to be covered

in a document this brief and there are exemptions for certain applications to be considered as well. Please

consider this document as general guidance, the regulating body for this legislation in Ontario is the TSSA.

(each Province has its own different regulating body) Contact information for both the TSSA and CSA are listed

at the end of this document.

What is a CRN? CRN stands for Canadian Registration Number and can be obtained for either a Registered

Pressure Vessel or a Registered Fitting. A heat exchanger can be considered a Pressure Vessel (ASME), a

Fitting or neither. The information below is derived from the CSA B51 Standard, which is Canada wide, but each Province has its own registration requirements.

It is recommended that the end user clearly understand the jurisdictional requirements before making the

decision whether a heat exchanger is a pressure vessel, fitting or does not need to be registered. Manufacturing

a heat exchanger with an ASME stamp if it is not required can add considerable cost to a project, so can delays

in starting a process because one of the heat exchangers does not have a CRN.

Listed below are thee flow charts to help determine the classification of a specific heat exchanger.

1) Every Province has a different assessment process to determine the classification. The heat exchanger

must satisfy the regulations of the province in which it would be installed.

2) Each Province has applications where a heat exchanger may be exempt depending on the service in

which it is installed. Sometimes these applications are unclear and difficult to interpret.

3) The classification of the heat exchanger is dependant on; the size, the fluids contained and design

pressure and temperature.


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For Heat Exchangers Containing Water or Liquids Not More Hazardous than Water

Figure 1

Is design pressure over 15 psig?

Is design temp, over

150F? ( 65c )

Is design press. over 250 psig?

( 1.72 Mpa)

Is design press, over 600 psig?

( 4.14 Mpa)

Is internal volume over1.5 cu.ft.? ( 42.5 l )

Is internal diameter over 6?

( 152 mm )

Heat Exchanger required to be registered as a pressure vessel and inspected by an Authorized Inspector

Heat Exchanger required to be registered as a category H fitting

A CRN is not required

Yes

No

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No


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For Heat Exchangers Containing Nonlethal Gas, Vapour or Liquid

Not Covered by Figure 1

Figure 2


Is design press, over 600 psig?

( 4.14 Mpa)



( 152 mm )




Yes

No

Yes

Yes

Yes

No

No

No

Is internal volume over1.5 cu.ft.? ( 42.5 l ) No

Yes


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For Heat Exchangers Containing Lethal Substances

Figure 3

More information: http://www.csa-intl.org/onlinestore/GetCatalogDrillDown.asp?Parent=1056 http://www.tssa.org/regulated/boilers/boilersSafety.asp?loc3=act http://www.tssa.org/regulated/boilers/boilersSafety.asp?loc3=act http://www.absa.ca/ http://www.asme.org/



( 152 mm )




Yes

Yes

No

No


Yes

No

Canadian Standard Association CSA B51

Technical Standards & Safety Authority of Ontario TSSA

Ontario Boiler & Pressure Vessel Regulation

Alberta Boilers Safety Association

American Society of Mechanical Engineers - ASME

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