Valves should be installed with the stems between the vertical and horizontal positions to remain accessible for operation and maintenance without obstructing personnel or traffic movement.
Valve hand-wheels, levers, instruments or other equipment requiring manual operation should be installed in safely accessible elevation/locations and should not obstruct access clearances in all operated positions. Valves should be installed so that the operator will not stand on adjacent pipes, cable trays, handrails or other equipment not meant to be used as a standing surface for the operation, maintenance, repair or replacement of the valve. Proper clearance for wrenches should be provided adjacent to flanged connections for valves and equipment.
Valve hand-wheel extensions and chain operators should only be used when a better alternative is unavailable. These mechanisms require maintenance and are subject to corrosion. Chain operators are a nuisance, may not operate in an emergency and can be a hazard if the chain is left off of its tie-back and hanging in an access way.
Piping systems should be constructed with flanged joints or unions, per applicable piping specifications, wherever frequent maintenance is required. Piping that requires servicing—more than once every 6 mos—should be arranged to preclude the undesired removal of equipment, piping or installation of temporary supports.
Piping connections to heat exchangers, compressors, pumps and locations where pigging and/or steam air decoking will be required should be designed to facilitate equipment removal by means of removable spools, preferably with a change in direction to ease extraction.
Piping supports should be designed to facilitate the removal of connected equipment, vessels, instrumentation and valves without compromising the support of adjacent piping, valves and appurtenances.
The identification and marking of field and shop welds on piping drawings assists the construction team, improves the quality of construction and maximizes shop welding, improving and simplifying inspection and quality assurance.
Strainers and filters are installed to facilitate smooth functioning of process equipment and must be cleaned as per process specified frequency. In many instances, opting for a duplex arrangement will allow for uninterrupted service while one is taken for cleaning. Installing self-cleaning strainers and filters with a duplex arrangement will allow for the optimum uninterrupted service if planned and considered from the design stage.
