This Part specifies the basic requirements for the safety protection devices (safety relief device and flame arrester) and safety protection of the pressure piping within the range of GB/T 20801.1.Other requirements on safety protection not specified in this Part shall comply with the requirements of the other parts of GB/T 20801-2006 and the current relevant standards and codes of the state.
2 Normative References
The following documents contain provisions which, through reference in this Part of GB/T 20801, constitute provisions of this Part. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties whose enter into agreement according to this Part are encouraged to research whether the latest editions of these references are applied or not. For undated references, the latest edition of the normative document is applicable to this standard.
GB 150 "Steel Pressure Vessels"
GB 567-1999 "Bursting Discs and Bursting Disc Devices"
GB 3836.12-1991 "Electrical Apparatus for Explosive Atmospheres-Classification of Gases or Vapors with Air According to Their Maximum Experimental Safe Gaps and Minimum Igniting Currents" (eqv IEC 60079-12: 1978)
GB/T 3840 "Technical Methods for Making Local Emission Standards of Air Pollutants"
GB 5908 "Flame Arresters for Petroleum Tanks"
GB 12158 "General Guideline for Preventing Electrostatic Accidents"
GB/T 12241-2005 "Safety Valves--General Requirements" (ISO 4126-1: 1991, MOD)
GB/T 12242-2005 "Performance Test Code--Pressure Relief Devices"
GB/T 12243-200 5 "Spring Loaded Safety Valves"
GB 13347-1992 "The Quenching Ability of Flame Arrester and Its Test Method for Petroleum Gas Piping Systems"
GB/T 20801.1-2006 "Pressure Piping Code-Industrial Piping-Part 1: General"
GB/T 20801.3-2006 "Pressure Piping Code-Industrial Piping-Part 3: Design and Calculation"
GB 50016-2006 "Code for Design of Building Fire Protection"
GB 50160 "Fire Prevention Code of Petrochemical Enterprise Design"
GB 50187 "Code for Design of General Plan of Industrial Enterprises"
HG/T 20570.2-1995 "Installation and Selection of Safety Valves"
SH/T 3413-1999 "Specification for Selection Inspection and Acceptance of Pipeline Flame Arresters for Petroleum Gas in Petrochemical Industry"
SY/T 10043-2002 "Guide for Pressure-relieving and Depressuring Systems"
SY/T 10044-2002 "Sizing Selection and Installation of Pressure-relieving Devices in Refineries"
3 Terms and Definitions
3.1
Safety relief device
On occasions with or without fire accidents, the safety relief device is opened to relieve liquid under the action of inlet static pressure so as to prevent the pressure in the system from exceeding the preset safe value. The safety relief device includes safety valve and rupture disk device.
3.2
Safety valve
The spring acted or pilot operated valves. It is a kind of safety relief device of which the valve clack will rise to relieve the liquid so as to prevent the pressure in system from exceeding the preset safe value when the static pressure at the inlet exceeds the set pressure and that can close automatically when the pressure falls to the re-seating pressure.
3.3
Rupture disk device
A kind of non-reclosed safety relief device composed of rupture disk and gripper, in which, the rupture disk will rupture or shed when the pressure difference between both sides of the rupture disk is as high as the preset value at preset temperature.
3.4
Set pressure of the safety valve
It is the inlet static pressure for the safety valve clack starting rising under the operating condition, also named as opening pressure or set pressure. Under this pressure, the measurable opening height starts to exist, the liquid is at the continuous discharge condition that can be sensed visually or aurally.
3.5
Maximum marked burst pressure
One same batch of qualified rupture disks are done with burst test at a certain temperature, and the maximum burst pressure obtained through the tests is the maximum marked burst pressure of this batch of rupture disks.
3.6
Maximum relieving pressure
The maximum inlet pressure when the safety valve clack reaches the specified opening height under the relieving condition. As for the rupture disk device, the maximum relieving pressure refers to the maximum pressure bear by the pressure system when the rupture disk cracks.
3.7
Required relief capacity
The flow capacity that the safety relief system in order to prevent excessive pressure of the system.
3.8
Relief area
The net flow area when the safety valve discharges or the rupture disk cracks.
3.9
Block valve; stop valve
The valve used for blocking or connecting the fluid in pipe. The common block valves include gate valve, ball valve, plug valve, butterfly valve, diaphragm valve as well as the stop valve with flat seat, large valve opening and small flow resistance.
3.10
Independent pressurize system
A pressure system composed of one or more equipments (containers) by pipe connection without the blocking of any valves at middle, both ends of this system are installed with valves to separate from other systems.
3.11
Flame arrester
A safety protection equipment used for preventing the flame from spreading or extending in the piping.
3.12
Venting flame arrester
It is installed on the vent pipe of storage tank to prevent external flame from entering into the storage tank, and it has the pipe end type and ordinary type.
The pipe-end type venting flame arresters are of the anti-conflagration type, with one end connected to the atmosphere, installed with wind-rain protective hood on the top to prevent the dust and rainwater from entering into the flame arrester.
The ordinary type venting flame arresters are divided into anti-conflagration type and anti-detonation type, with both ends connected with the piping and being connected with the atmosphere through the downstream piping.
3.13
Pipeline flame arrester
The pipeline flame arrester is installed in the closed pipe system to prevent the flame at one end of the piping system from spreading to the other end. It is divided into anti-detonation type and anti-detonation type.
3.14
Maximum experimental safe gap (MESG)
The minimum slit width that the flame can pass through under the standard test conditions (0.1MPa, 20℃) (the slit is 25mm long).
GB/T 20801.6-2006 The following standards are cited：
