Access Provisions-Process Unit and Offsites Layout

Minimum Access Provisions-Process Unit and Offsites Layout

Guide

Minimum Access	Type of Item to be Accessed
Platform - Items Located Over Platform	Elevated heat exchangers Elevated control valves (all sizes) Manholes (higher than 3658 mm (12 ft.) above grade) Relief valves (NPS 102 mm (4”) inlet and larger on vertical vessel) Process blinds (higher than 3658 mm (12 ft.) above grade) Furnace soot blowers Furnace burners (when not accessible from grade) Furnace observation doors and sample ports (higher than 3658 mm (12 ft.) above grade) Elevated cleanouts
Platform - Items Located at Edge of Platform	NPS 102 mm (4”) and larger gate and globe valves at vessels Battery limit valves in elevated pipe racks Elevated motor operated valves Relief valves - NPS 77 mm (3”) inlet and smaller on vertical vessels Relief valves - All sizes on horizontal vessels Level controllers (higher than 3658 mm (12 ft.) above grade) Sampling devices on vessels (higher than 3658 mm (12 ft.) above grade)
Permanent Ladder	All sizes of check valves at vessels NPS 77 mm (3”) and smaller gate and globe valves at vessels Level controllers between 2134-3658 mm (7-12 ft.) above grade Level gauges and valves Furnace observation ports between 2134-3658 mm (7-12 ft.) above grade Instruments requiring routine access Handholes Elevated electrical substations and equipment
Mobile Stair	All servicing between 2134-3658 mm (7-12 ft.) above grade except as noted in this Table
No Permanent Access	Block valves in pipe racks (except at battery limit) Elevated orifices or meter runs Nozzles on vessels (without process blinds or valves) Check valves not at vessels Temperature connections in piping Pressure connections in piping Silencers or exhaust heads Metal temperature measuring points on vessels Instrument connections on furnaces