Antony,
Both your references supplied:
Reference: 8.3.1.k
Environmental Protection for Onshore Oil and Gas Production Operations and Leases
API RECOMMENDED PRACTICE 51R
FIRST EDITION, JULY 2009
and
Reference:5.8.c.1
Recommended Practice for Design and Installation of Offshore
Production Platform Piping Systems
API RECOMMENDED PRACTICE 14E (RP 14E)
FIFTH EDITION, OCTOBER 1, 1991
appear to be the opposite of what is regarded as good engineering practice – and what others on this topic have said.
That being said, there are a number of factors to consider, not least of of site personnel safety – and each plant will have its own particular set of challenges.
In a large refinery plant, where there is plenty of space, an “Upwind” location would negate any hydrocarbon gas leakage from process being transferred to flare stack which is a source of ignition for these gases.
Offshore however, ‘Downwind’ may be preferable, so as to avoid any dangers/ill-effects to plant& personnel;
There are no nearby properties so the chances/possibilities of a nearby adjoining property “going up” are remote.
Regardless of rules and codes, every project must be looked at on its own merits …
Someone said once (probably JOP)
There is a rule for everything in piping … and for every rule, there is an exception!