1 Scope
This specification specifies air source for instrument, operating pressure, air supply volume, air supply method and the minimum requirements for the piping design of air supply system.
This specification is applicable to the design of air sources and air supply systems required for automatic control instrument for new construction, expansion and renovation projects of petrochemical industries.
2 Normative references
The following documents are indispensable for the application of this specification. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 4830-1984 Pressure range and quality of air supply for the industrial process measurement and control instruments
TSGR 0004-2009 Supervision regulation on safety technology for stationary pressure vessel
3 Terms and definitions
For the purposes of this specification, the following terms and definitions apply.
3.1
air source
pressurized gas (usually air) that maintains the operation of the instrument or actuator
3.2
air supply system
piping network that connects the air source to the instrument for the supply of air to the instrument
3.3
air consumption
air flow consumed by the instrument during operation
3.4
static air consumption
maximum flow of the air consumed by the instrument in its operating range at static state
3.5
output pressure
pressure on the outlet line (behind the pressure reducing valve, if any) of the final filter of the air source unit
3.6
lowest pressure of air supply
lower limit of the pressure delivered by the air source unit when the instrument or actuator maintains normal operation
3.7
maintenance time
duration in which the pressure of the air supply network is maintained at a level higher than the minimum output pressure by the air stored in the air storage tank when the air supply unit is shut down
3.8
battery limit input pressure
pressure of the air supply line at the battery limit input
3.9
air source unit
process unit that provides air source for the operation of instrument or actuator
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Air source unit
4.1 Quality requirements of the air source
4.2 Volume of air source unit
4.3 Pressure of the air source
4.4 Requirements for safe use of air
4.5 Air storage tank
5 Design of air supply system
5.1 Philosophy for air supply system design
5.2 Method of air supply
6 Piping design for air supply system
6.1 Selection of material for air supply piping
6.2 Selection of diameter for air supply pipe
6.3 Installation requirement for air supply pipeline
6.4 Air source connections and valve installation
Explanation of wording in this specification
