Spacing Between Equipment In Gas Processing Plants

I doubt that any one standard or code will cover this. For electrical cabinets, there are standards for clear space in front. On a skid, if all serviceable parts face outward, little or no internal clearance will be needed. Manufacturers will usually tell how much clearance is needed for removing pistons, filter elements, etc. Safety standards may dictate the width of walkways between pieces of equipment. And so on. You will probably need to combine several sources of information.

Ease in maintenance, operability is necessary requirement and not too much space is required but safe distances is separate thing and why we have to consider this in processing plants and not in skid packages.

You need a tour of duty in a submarine.

You too.

Exactly.

As a rough rule of thumb, look at all the appropriate codes/manuals to find the largest clearance required from each side/end, then take that and add 20%. When the bean counters complain, you 'compromise' by falling back to 10% over, but tell them that reduction will likely increase the length of downtime by 30-50% as the equipment will not have room to install/remove larger components easily.

If you're in the US, then I'd go with +50%/+30%, and the reason for not going further is that it could lead to fines if an OSHA inspector is unhappy with the spacing.

Try with API 2510 (Point 5.1.2) and API 752 chapter 6.
May be there is the answer to your question.
WP

Skid planning, design and troubleshooting are the skills being offered by major engineering firms.

There is no single "calculation" or "design practice" that will teach you this. Properly designed gas process skids involve a variety of engineering skills including mechanical, electrical, structural and instrumentation specialties.

http://www.worleyparsons.com/CSG/Hydrocarbons/SpecialtyCapabilities/Documents/Gas_Processing_Brochure.pdf

What is this 'skid planning'? Are we talking about building modules on - for lack of a better analogy - big metal shipping pallets? I guess that could lead to more flexibility in the plant, as you move modular units around to reconfigure for this or that. But even then, you'd need access to the 'interior components' for maintenance, unless 'maintenance' means pulling an entire skid into the shop and disassembling it for routine work.

Refer to NFPA Fire Code #1 - from there on you can get number f cross referenced doc say API 2510 etc. HAZOP / HAZID studies would help you get to correct / revise after through exercises.

Kindly remember that local jurisdictional laws prevail over these code provisions unless otherwise the operator states so.