Pressure Piping Code - Industrial Piping - Part 6: Safeguarding
压力管道规则 工业管道 第6部分：安全防护
1 Scope
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).
4 Safety Relief Device
4.1 General Requirements
4.1.1 The installed safety relief device shall be able to prevent the system or any one part from having excess pressure accident.
4.1.2 Generally, the automatic control instrument and accident interlocking device shall not replace the safety relief device to act as the protective equipments of the system, however, the cases that the safety relief device can not be installed and the reliability of control instrument or interlocking device is no less than that of the safety relief device are excluded.
4.1.3 When installing the safety relief device, the factors may causing excess pressure shall be considered:
a) The outlet of equipment piping system is closed;
b) The public works (cooling water, electricity, vapor, instrument air, inert gas and fuel oil/gas) are out of order;
c) The equipments and instruments (pump, compressor, fan, heat exchanger, air cooler system, transmitter, controller, control valve and alarm interlocking device, etc) are out of order;
d) Thermal expansion and phase change of liquid;
e) Out-of-control exothermic reaction;
f) Misoperation of operation personnel;
g) Accumulation of non-condensable gas;
h) Volatile substances enter into the system (light hydrocarbon or water enters into the hot oil, etc);
i) External fires, etc;
4.1.4 The safety relief device shall be installed if any one of the following conditions is met:
a) The equipment and piping system of which the design pressure is less than the pressure of external pressure source and the outlet may be closed or blocked;
b) The outlet piping of the positive displacement pump and compressor, of which the outlet may be closed;
c) The gas-phase piping at top of distillation tower which causes excess pressure by the interrupted cooling water or backflow or the excess heat input of reboiler;
d) The equipment and piping system with excess pressure due to the accumulation of non-condensable gas;
e) The upstream pipings of block valve or control valve in the outlet piping of heating furnace;
f) The piping system producing thermal expansion or vaporization due to the closed block valves at both ends under the influence of ambient temperature, sunshine radiation or heat tracing;
g) The upstream piping system of block valve at the outlet of such reactor of which the exothermic reaction may be out of control;
h) The steam outlet piping of condensing steam turbine;
i) The outlet piping of the equipments producing steam, such as steam generator;
j) The outlet piping of the low boiling point liquid (liquefied gas, etc) container;
k) The outlet piping on the on low pressure side of heat exchanger of which the tube pass may crack;
l) Other positions where the designer thinks excess pressure may generate.
4.1.5 The independent pressurize system shall be installed with one or more parallel safety relief devices (depending on the relieving capacity) at the proper positions (equipments or piping).
4.1.6 The relevant pressure of safety relief device shall be determined in accordance with the following requirements.
4.1.6.1 As for the safety relief devices on the piping in independent pressurize system, the relevant pressure shall be determined based on the design pressure of the system and shall meet the following requirements:
a) Where only one safety relief device is installed, the set pressure of safety valve (or the maximum marked burst pressure of rupture disk device) shall not be larger than the design pressure of the system, and the maximum relieving pressure shall not be larger than shall not be larger than the larger value between 10% of the system design pressure and 20kPa.
b) Where more than one safety relief devices are installed, the set pressure of at least one safety valve (or the maximum marked burst pressure of rupture disk device) shall not be larger than the design pressure of the system, and the set pressure of the rest safety valves (or the maximum marked burst pressure of rupture disk devices) shall not exceed 5% of the system design pressure, and the maximum relieving pressure of all the safety valves shall not be larger than the larger value between 12% of the system design pressure and 30kPa.
c) The maximum relieving pressure of those safety relief devices that are installed for preventing fire accidents shall not be larger than 16% of the system design pressure.
4.1.6.2 As for the safety relief devices installed for preventing the thermal expansion of fluid piping, the set pressure of the safety valves (or the maximum marked burst pressure of rupture disk devices) shall not be larger than the smaller value between 120% of the piping design pressure and the system test pressure, and the maximum relieving pressure shall not exceed 20% of the rating value of pipe pressure at the corresponding temperature or the nominal stress of piping produced by pressure shall not exceed 20% of the allowable stress of materials.
4.1.6.3 Except for the above-mentioned two kinds of cases, with the requirements specified in 4.2.3.1~4.2.3.8 of GB/T 20801.3-2006 being met, the maximum relieving pressure shall not exceed the variation range of allowable pressure as specified in 4.2.3.9 and 4.2.3.10 of GB/T 20801.3-2006.
4.1.6.4 The set pressure of the safety valves of Leve-GC1 piping (or the maximum marked burst pressure of rupture disk devices) shall not be larger than the design pressure of piping, and the maximum relieving pressure of safety valves shall not exceed 10% of the design pressure.
4.1.7 The determination of required relief capacity and minimum relief area shall meet the following requirements.
4.1.7.1 The required relief capacity shall be determined according to the following requirements:
a) The required relief capacity under various excess pressure conditions shall be calculated according to the material balance and energy balance.
b) If one position in the system has several kinds of excess pressure conditions, then the required relief capacity under each kind of excess pressure condition shall be calculated respectively, among which the maximum value shall be taken as the required relief capacity of this position.
c) The calculation of required relief capacity shall comply with those specified in Appendix A; the required relief capacity under the excess pressure conditions not provided in Appendix A may be calculated by making reference to the corresponding provisions in SY/T 10043-2002, SY/T 10044-2002 and HG/T 20570.2-1995.
4.1.7.2 The minimum relief area shall be determined according to the following requirements:
a) The minimum relief area shall be calculated according to the required relief capacity, maximum relieving pressure, temperature of relieved fluid, rated relieving coefficient and physical properties of fluid.
b) The minimum relief area of safety valve and rupture disk device shall be calculated according to those specified in Appendix A of this Part.
c) The actual relief area of the selected safety relief device shall not be less than the minimum relief area.
4.1.8 The safety relief device shall not be installed with block valves on its inlet or outlet side. The block valves to be installed for the testing, maintenance and replacement of safety relief device shall meet the following requirements:
a) The full bore block valves shall be installed or the pressure fall of block valves shall not affect the normal operations and the required relieving capacity of safety relief device.
b) The block valves at the fully open or close position shall be able to be locked or lead sealed, the block valves at normal operations shall be locked or lead sealed at the fully open position, and they shall be closed under the supervision of authorized personnel.
4.1.9 The inlet piping of safety relief device shall meet the following requirements:
a) The pipe diameter shall be at least equal to the inlet size of safety relief device, and the inlet piping shall be as short as possible.
b) Where safety relief devices are installed on the outlet piping of reciprocating compressor, the ripple damper or orifice plate shall be installed abutting upon the compressor, and the distance between the ripple damper or orifice plate and the straight pipe segment of safety relief device shall be at least 10 times of the pipe diameter.
4.1.10 The outlet piping of safety relief device shall meet the following requirements:
a) The piping outlet relieving into the atmosphere shall face towards safe sites, the relieving piping and the pipe support shall have adequate strength to bear the relieving counterforce.
b) The backpressure of the outlet piping and main relieving pipe connected to the closed system (into the exhaust funnel, flare system, collecting container or other processing systems through the main relieving pipe) shall not exceed the maximum allowable backpressure of safety relief device.
c) The low-temperature brittle failure affect of the shock cooling of low boiling point liquid (liquefied gas, etc) sue to depressurization and flash vaporization on the piping material shall be taken into account.
1 Scope
2 Normative References
3 Terms and Definitions
4 Safety Relief Device
4.1 General Requirements
4.2 Selection of Safety Relief Device
5 Flame Arrester
5.1 Installation of Flame Arrester
5.2 Requirements for Selection of Flame Arrester
6 Safety Protection
6.1 General Requirements
6.2 Safety Protection in Plant Layout
6.3 Safety Protection in Production Management
6.4 Safety Protection Facilities and Measures
Appendix A (Normative) Calculation of Safety Relief Device
第6部分：安全防护
1范围
本部分规定了GB／T 20801.1 范围内压力管道的安全保护装置(安全泄放装置、阻火器)和安全防护的基本要求。本部分未规定的其他安全防护要求应符合本标准其他部分以及国家现行有关标准、规范的规定。
2规范性引用文件
下列文件中的条款通过GB／T 20801的本部分的引用而成为本部分的条款。凡是注日期的引用文件，其随后所有的修改单(不包括勘误的内容)或修订版均不适用于本部分，然而，鼓励根据本部分达成协议的各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本部分。
GB 150钢制压力容器
GB 567—1999爆破片和爆破片装置
GB 3836.12—1991爆炸性环境用防爆电器设备 气体或蒸汽混合物按照其最大试验安全间隙和最小点燃电流的分级(eqv IEC 60079—12:1978)
GB／T 3840制定地方大气污染物排放标准的技术方法
GB 5908石油储罐阻火器
GB 12158防止静电事故通用导则
GB／T 12241—2005安全阀一般要求(ISO 4126-1:1991，MOD)
GB／T 12242—2005压力释放装置 性能试验规范
GB／T 12243—2005 弹簧直接载荷安全阀
GB 13347—1992 石油气体管道阻火器性能和试验方法
GB／T 20801.1—2006 压力管道规范 工业管道 第1部分：总则
GB／T 20801.3—2006 压力管道规范 工业管道 第3部分：设计和计算
GB 50016—2006 建筑设计防火规范
GB 50160 石油化工企业设计防火规范
GB 50187 工业企业总平面设计规范
HG／T 20570.2—1995 安全阀的设置和选用
SH／T 3413—1999 石油化工石油气管道阻火器选用、检验及验收
sY／T 10043—2002 泄压和减压系统指南
SY／T 10044—2002 炼油厂压力泄放装置的尺寸确定、选择和安装的推荐做法
3． 术语和定义
3.1
安全泄放装置 safety relief device
在非火灾或火灾事故情况下，安全泄放装置籍进口静压力作用开启，泄放流体，以防止系统内压力超过预定的安全值。安全泄放装置包括安全阀及爆破片装置。
3.2
安全阀 safety valve
由弹簧作用或导阀控制的阀门。当入口处的静压超过设定压力时，阀瓣上升，流体泄放，以防止系统内压力超过预定的安全值，当压力降至回座压力时，可自动关闭的一种安全泄放装置。
3.3
爆破片装置 rupture disk device
由爆破片和夹持器组成的一种不重新闭合的安全泄放装置，当爆破片两侧的压力差达到预定温度下的预定值时，爆破片发生破裂或脱落。
3.4
安全阀设定压力 set pressure of the safety valve
在运行条件下安全阀阀瓣开始升起的进口静压力，又称为开启压力或整定压力。在该压力下，开始有可测量的开启高度，流体呈可由视觉或听觉感知的连续排出状态。
3.5
最大标定爆破压力 maximum marked burst pressure
同一批次的合格爆破片，在一定温度下进行爆破试验，试验得到的最大爆破压力为这一批次爆破片的最大标定爆破压力。
3.6
最大泄放压力 maximum relieving pressure
在泄放状态下，安全阀的阀瓣达到规定开启高度时的最大进口压力。对于爆破片装置，最大泄放压力系指爆破片发生破裂时压力系统承受的最大压力。
3.7
安全泄放量 required relief capacity
为了防止系统超压，安全泄放系统必须泄放的流量。
3.8
泄放面积 relief area
安全阀泄放时或爆破片破裂时的净流通面积。
3.9
切断阀 block valve; stop valve
用于隔断或连通管内流体的阀门。常用的切断阀包括闸阀、球阀、旋塞阀、蝶阀、隔膜阀以及阀孔大且流阻小的平面阀座截止阀。
3.10
独立压力系统 independent pressurize system
由一个或多个设备（容器）采用管道连接且中间无阀门隔断的压力系统，其两端设有可与其他系统隔断的阀门。
3.11
阻火器 flame arrester
阻止火焰在管道内传播和蔓延的安全防护设备。
3.12
放空阻火器 venting flame arrester
安装在储罐的放空管道上，用以防止外部火焰传入储罐内，分为管端型和普通型。
管端型放空阻火器为阻爆燃型，其一端与大气相通，且顶部安装防风雨帽，以防止灰尘和雨水进入阻火器内部。
普通型放空阻火器分为阻爆燃型和阻爆轰型，其两端与管道相连，通过下游管道与大气相通。
3.13
管道阻火器 pipeline flame arrester
安装在密闭管道系统中，用以防止管道系统一端的火焰蔓延到另一端。分为阻爆燃型和阻爆轰型。
3.14
最大试验安全间隙 maximum experimental safe gap (MESG)
标准试验条件下（0.1MPa、20℃），火焰不能通过的最小狭缝宽度（狭缝长为25mm）。
4 安全泄放装置
4.1 一般规定
4.1.1安装的安全泄放装置应能够防止系统或其中的任一部分发生超压事故
4.1.2自动控制仪表和事故联锁装置一般不得代替安全泄放装置作为系统的保护设施，但无法安装安
全泄放装置且控制仪表或联锁装置的可靠性不低于安全泄放装置的情形除外。
4.1.3安装安全泄放装置时，应考虑可能产生的超压因素：
a）设备或管道系统出口关闭；
b）公用工程（冷却水、电、蒸汽、仪表空气、惰性气体和燃料油/气等）故障；
c）设备和仪表（泵、压缩机、风机、热交换器、空冷器系统，以及变送器、控制器，调节阀和报警联锁装置等）故障；
d）液体热膨胀和流体相变；
e）放热反应失控；
f）操作人员误操作；
g）不凝气体的积聚；
h）易挥发物质进入系统（轻烃或水进入热油等）；
i）外部火灾等。
4.1.4符合下列情况之一者，应设置安全泄放装置的处所：
a）设计压力小于外部压力源的压力，出口可能被关断或堵塞的设备和管道系统；
b）出口可能被关断的容积式泵和压缩机的出口管道；
c）因冷却水或回流中断，或再沸器输入热量过多而引起超压的蒸馏塔顶的气相管道；
d）因不凝气体积聚产生超压的设备和管道系统；
e）加热炉出口管道中切断阀或调节阀的上游管道；
f）因两端切断阀关闭，受环境温度、阳光辐射或伴热影响而产生热膨胀或汽化的管道系统；
g）放热反应可能失控的反应器出口处切断阀上游的管道系统；
h）凝汽式汽轮机的蒸汽出口管道；
i）蒸汽发生器等产汽设备的出口管道；
j）低沸点液体（液化气等）容器的出口管道；
k) 管程可能破裂的热交换器低压侧的出口管道；
l) 设计者认为可能产生超压的其他部位。
4.1.5独立压力系统应在适当的位置（设备或管道）设置一个或多个并联（视泄放量而定）的安全泄放装置。
4.1.6 安全泄放装置的相关压力应按一下规定确定。
4.1.6.1 对于独立压力系统中管道上的安全泄放装置，相关压力的确定应以系统的设计压力为基准，且符合以下规定。
a）当安装一个安全泄放装置时，安全阀的设定压力（或爆破片装置最大标定爆破压力）应不大于系统设计压力，且最大泄放压力应不大于系统设计压力的10%和20 kPa中的较大者。
b）当安装多个安全泄放装置时，至少有一个安全阀的设定压力（或爆破片装置最大标定爆破压力）应不大于系统设计压力，其余安全阀设定压力（或爆破片装置最大标定爆破压力）不得超过系统设计压力的5%，且安全阀最大泄放压力均应不大于系统设计压力的12%或30 kPa中的较大者。
c）为防止火灾事故发生而安装的安全泄放装置，且最大泄放压力应不大于系统设计压力的16%。
4.1.6.2 对于防止液体管道热膨胀的安全泄放装置，安全阀设定压力（或爆破片装置最大标定爆破压力）应不大于管道设计压力的120%和系统试验压力中的较小值，且最大泄放压力应不超过相应温度下管道压力额定值的20%或由压力产生的管道名义应力不超过材料许用应力值的20%。
4.1.6.3 除上述两种情况外，在满足GB/T 20801.3-2006中 4.2.3.1~4.2.3.8要求的条件下，最大泄放压力应不超过GB/T20801.3-2006中 4.2.3.9和4.2.3.10规定的允许压力变动范围。
4.1.6.4 GC1级管道安全阀的设定压力（或爆破片装置的最大标定爆破压力）应不大于管道设计压力，安全阀的最大泄放压力应不超过设计压力的10％。
4.1.7 安全泄放量和最小泄放面积的确定应符合以下规定。
4.1.7.1 安全泄放量应按以下规定确定：
a) 应根据物料平衡和能量平衡，计算各种超压工况的安全泄放量。
b) 若系统的某个部位有几种超压工况，则应分别计算每种超压工况的安全泄放量，并取其中的最大值为该部位的安全泄放量。
c) 安全泄放量的计算应符合附录A的规定；附录A中未规定的其他超压工况的安全泄放量计算，可参照SY/T l0043—2002、SY/T 10044—2002和HG/T 20570.2—1995的相应规定。
4.1.7.2最小泄放面积应按以下规定确定：
a) 根据安全泄放量、最大泄放压力、泄放流体温度、额定泄放系数以及流体的物理性质，计算最小泄放面积。
b) 安全阀和爆破片装置的最小泄放面积应按本部分附录A的规定计算。
c) 选用的安全泄放装置的实际泄放面积应不小于最小泄放面积。
4.1.8安全泄放装置的进、出口侧不得安装切断阀。因安全泄放装置检测、维修和更换需要安装的切断阀应符合下列要求：
a) 切断阀应是全通径的，或者其压力降不会影响安全泄放装置的正常工作和要求的泄放量。
b) 在全开或关闭位置切断阀应能被锁定或铅封，正常工作时切断阀应被锁定或铅封在全开位置，关闭应在授权人员的监督下进行。
4.1.9 安全泄放装置的入口管道应满足以下规定：
a）管径至少应等于安全泄放装置的进口尺寸，入口管道的长度应尽可能短。
b）在往复式压缩机排出口管道上安装安全泄放装置时, 脉动阻尼器或孔板的设置应紧靠压缩机，且脉动阻尼器或孔板至安全泄放装置的直管段的距离至少应为10倍的管径。
4.1.10 安全泄放装置的出口管道应满足以下规定：
a）泄放至大气的管道出口应朝向安全地点，泄放管道及其支承应有足够的强度承受泄放反力。
b) 排放至密闭系统（经泄放总管至排气筒、火炬系统、收集容器或其他处理系统）的出口管道和泄放总管的背压应不超过安全泄放装置允许的最大背压。
c) 应考虑因低沸点液体(液化气等)在降压闪蒸时产生骤冷对管道材料的低温脆断影响。
4.2 安全泄放装置的选用
4.2.1 安全阀的选用应符合一下规定：
a) 安全阀适用于清洁、无颗粒和低黏度的介质；
b) 安全阀应按泄放介质的状态(气／汽或液体)选用，并考虑背压的影响；
c) 安全阀的选用应符合GB 150、GB 12241—2005、GB 12242—2005及GB 12243—2005的
规定。
4.2.2 以下情况应选用爆破片装置，并应符合GB 150及GB 567的规定。
a) 压力可能迅速上升的场合；
b) 含有颗粒、易沉淀、易结晶、易聚合、黏度大的介质；
c) 工作压力很低或很高的场合，且安全阀难以满足要求；
d) 因强腐蚀性介质而需要使用贵重材料时；
e) 使用温度较低而影响安全阀的工作性能时;
f) 需要较大的泄放面积；
g) 不允许有泄漏的场合。
4.2.3 以下情况应采用爆破片装置和安全阀的组合装置：
a) 串联使用(爆破片装置在安全阀入口)
1) 保护安全阀不受工艺介质腐蚀、堵塞或其他不利因素影响；
2) 防止安全阀泄漏；
3) 减少爆破片破裂后的泄放损失；
4) 安全阀的在线检测。
b) 串联使用(爆破片装置在安全阀出口)
保护安全阀不受泄放总管中气体的腐蚀。
c) 并联使用
爆破片装置作为火灾工况的辅助安全泄放装置。
5 阻火器
5.1 阻火器的设置
5.1.1 下列放空或排气管道上应设置放空阻火器：
a）闪点不大于43℃或物料的最高工作温度不小于物料闪点的与储罐直接相连的放空管道（含带有呼吸阀的放空管道）。确定物料的最高工作温度时，应考虑环境、阳光照射和加热装置失控等因素；
b）可燃气体在线分析设备的放空总管；
c）进入爆破危险场所的内燃发动机的排气管道。
5.1.2 符合下列条件之一者应在管道系统的指定位置设置管道阻火器：
a）输送有可能产生爆燃或爆轰的爆炸性混合气体的管道（应考虑可能的事故工况），管道阻火器应设置在接受设备的入口处；
b）输送能自行分解爆炸并引起火焰蔓延的气体管道（如乙炔），管道阻火器应设置在接受设备的入口或试验确定的能阻止爆炸的最佳位置处；
c）火炬排放气进入火炬头前，应设置阻火器或阻火装置。
5.2 阻火器的选用规定
5.2.1 选用阻火器时，其最大间隙应不大于介质在操作工况（压力、温度、管道尺寸、长度、形状，及阻火器安装位置与点火源的距离）下的最大试验安全间隙（MESG）。爆炸性气体混合物的技术安全等级应符合GB3836.12—1991的规定，最大试验安全间隙（MESG）应符合表1的规定。
表1最大试验安全间隙（MESG）分级表 单位为毫米
级别 最大试验安全间隙（MESG）
II A ≥0.90
II B 0.90>MESG>0.50
II C ≤0.50
5.2.2 阻火器的选用还应符合GB 13347—1992，GB 5908和SH/T 3413—1999的规定。
6．安全防护
6.1 一般规定
采取安全防护措施时，应考虑以下因素：
a）由流体性质以及操作压力和操作温度确定的流体危险性；
b）由管道材料、结构、连接形式及其安全运行经验确定的管道安全性；
c）管道一旦发生损坏或泄漏，导致流体的泄漏量及其对周围环境、设备造成的危害程度；
d）管道事故对操作人员、维修人员和一切可能接触人员的危害程度。
6.2 工厂布置中的安全防护
a）露天化的设备布置应符合以下规定：
1）生产区和居民区之间、装置之间，建、构筑物之间以及设备之间应保持一定的安全距离；2）装置内的主要行车道，消防通道以及安全疏散通道的设置应符合国家标准GB50187、GB 50160和GBJ16的规定。
3）应对接近生产装置的人员予以控制；
4）应设置必要的坡度、排放沟、防火堤和隔堤；
b）可燃、有毒流体应排入封闭系统内，不得直接排入下水道及大气；
c）密度比环境空气大的可燃气体应排入火炬系统，密度比环境空气小的可燃气体，在不允许设置火炬及符合卫生标准的情况下，可排入大气。
d）可燃气体管道的放空管管口及安全泄放装置的排放位置应符合GB50160以及GB/T3840的规定；
e ) 架空管道穿过道路、铁路及人行道等的净空高度，以及外管廊的管架边缘至建筑物或其他设施的水平距离应符合GB50160、GBJ16及GB50187的规定，管道与高压电力线路间交义净距应符合架空线路相关标准的规定；
f）位于通道、道路和铁路上方的管道不应安装阀门、法兰、螺纹接头以及带有填料的补偿器等可能发生泄漏的管道组成件；
g）在可通行管沟内不得布置GC1级管道；
