Utility stations are required throughout the plant at various levels for supplying utility services like nitrogen, plant air, water and steam. Utility stations are so distributed that any vessel can be supplied with utility services with hoses of 15 meter length.
Nitrogen is an inert gas. It is required for purging services. When a particular vessel is taken out of service for maintenance purpose, all gases inside it must be purged with nitrogen. Care must be taken that all nitrogen is removed after purging before any maintenance personnel can enter the vessel, otherwise due to lack of oxygen, service personnel may die.
Plant air is used for various cleaning purposes like cleaning of shell and tube heat exchanger tubes, plate heat exchanger tubes etc. It is also used for cleaning of tanks.
Service water is used for cleaning purpose like cleaning of shell and tube heat exchanger tubes, general cleaning of floors, vessels etc.
Steam is used for cleaning of vessels, heating of parts of vessels, cleaning of tubes of heat exchangers etc.
Air and water lines typically have quick type hose connection and steam line have flanged type hose connection. These connections shall be directed downward. All connections shall have globe valve for isolation purpose. Inert gas hose like nitrogen, when required, shall have built in non return valve and quick coupling at pipe end.
- Normally, a 3/4″ hose connections are used for utility stations.
- Material of construction for hose connections is carbon steel.
- For air, water and nitrogen, piping side connection is normally female threaded.
- For steam, piping side connection isnormally Male Threaded.
- For Steam, Air and Water, hose side connection is Female Quick Connection.
- For nitrogen, hose side connection is normally Male quick coupling.
- Dimensions of hose connections and hoses are as per manufacturers own standard.
- Length of utility station hoses is normally 25 Meters.
- Hose for steam is made of stainless steel braiding and connection to utility station is Male quick coupling. Other side is female threaded end.
- Hose for nitrogen service is normally made of rubber, with utility station side connection as Female quick connect and other side as Male threaded end.
- Hoses for Air and Water are made of rubber, with utility station connection of Male quick connect and other side as male threaded end.
Number of Utility Stations
Number of utility stations shall be such that all equipments shall be approachable from at least one utility station. The approach of utility station shall be considered 15M all around the station location.
The Utility stations shall generally be located adjacent to pipe-rack column. The utility stations shall also be provided on elevated structures like technological structure, operating platforms of vertical equipments etc. Operating platforms having manholes must be accessible from utility station. Utility stations shall be located at loading racks.