Are TEMA Requirements Applicable to WHRU Design?

Hi all,

I'm currently design the WHRU for hot oil system. In client project spec, one of the standard to be reffered is TEMA. But, in my opinion TEMA requirement is not applicable with the WHRU design. This is because WHRU will not contain high pressure. The exhaust gas will only pass through the tube bundle. Appreciate if someone can advise me on this matter. TQ.