Pressure Piping Code - Industrial Piping - Part 6: Safeguarding
壓力管道規則 工業管道 第6部分：安全防護
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：安全防護
1范圍
本部分規定了GB／T 20801.1 范圍內壓力管道的安全保護裝置(安全泄放裝置、阻火器)和安全防護的基本要求。本部分未規定的其他安全防護要求應符合本標準其他部分以及國家現行有關標準、規范的規定。
2規范性引用文件
下列文件中的條款通過GB／T 20801的本部分的引用而成為本部分的條款。凡是注日期的引用文件，其隨后所有的修改單(不包括勘誤的內容)或修訂版均不適用于本部分，然而，鼓勵根據本部分達成協議的各方研究是否可使用這些文件的最新版本。凡是不注日期的引用文件，其最新版本適用于本部分。
GB 150鋼制壓力容器
GB 567—1999爆破片和爆破片裝置
GB 3836.12—1991爆炸性環境用防爆電器設備 氣體或蒸汽混合物按照其最大試驗安全間隙和最小點燃電流的分級(eqv IEC 60079—12:1978)
GB／T 3840制定地方大氣污染物排放標準的技術方法
GB 5908石油儲罐阻火器
GB 12158防止靜電事故通用導則
GB／T 12241—2005安全閥一般要求(ISO 4126-1:1991，MOD)
GB／T 12242—2005壓力釋放裝置 性能試驗規范
GB／T 12243—2005 彈簧直接載荷安全閥
GB 13347—1992 石油氣體管道阻火器性能和試驗方法
GB／T 20801.1—2006 壓力管道規范 工業管道 第1部分：總則
GB／T 20801.3—2006 壓力管道規范 工業管道 第3部分：設計和計算
GB 50016—2006 建筑設計防火規范
GB 50160 石油化工企業設計防火規范
GB 50187 工業企業總平面設計規范
HG／T 20570.2—1995 安全閥的設置和選用
SH／T 3413—1999 石油化工石油氣管道阻火器選用、檢驗及驗收
sY／T 10043—2002 泄壓和減壓系統指南
SY／T 10044—2002 煉油廠壓力泄放裝置的尺寸確定、選擇和安裝的推薦做法
3． 術語和定義
3.1
安全泄放裝置 safety relief device
在非火災或火災事故情況下，安全泄放裝置籍進口靜壓力作用開啟，泄放流體，以防止系統內壓力超過預定的安全值。安全泄放裝置包括安全閥及爆破片裝置。
3.2
安全閥 safety valve
由彈簧作用或導閥控制的閥門。當入口處的靜壓超過設定壓力時，閥瓣上升，流體泄放，以防止系統內壓力超過預定的安全值，當壓力降至回座壓力時，可自動關閉的一種安全泄放裝置。
3.3
爆破片裝置 rupture disk device
由爆破片和夾持器組成的一種不重新閉合的安全泄放裝置，當爆破片兩側的壓力差達到預定溫度下的預定值時，爆破片發生破裂或脫落。
3.4
安全閥設定壓力 set pressure of the safety valve
在運行條件下安全閥閥瓣開始升起的進口靜壓力，又稱為開啟壓力或整定壓力。在該壓力下，開始有可測量的開啟高度，流體呈可由視覺或聽覺感知的連續排出狀態。
3.5
最大標定爆破壓力 maximum marked burst pressure
同一批次的合格爆破片，在一定溫度下進行爆破試驗，試驗得到的最大爆破壓力為這一批次爆破片的最大標定爆破壓力。
3.6
最大泄放壓力 maximum relieving pressure
在泄放狀態下，安全閥的閥瓣達到規定開啟高度時的最大進口壓力。對于爆破片裝置，最大泄放壓力系指爆破片發生破裂時壓力系統承受的最大壓力。
3.7
安全泄放量 required relief capacity
為了防止系統超壓，安全泄放系統必須泄放的流量。
3.8
泄放面積 relief area
安全閥泄放時或爆破片破裂時的凈流通面積。
3.9
切斷閥 block valve; stop valve
用于隔斷或連通管內流體的閥門。常用的切斷閥包括閘閥、球閥、旋塞閥、蝶閥、隔膜閥以及閥孔大且流阻小的平面閥座截止閥。
3.10
獨立壓力系統 independent pressurize system
由一個或多個設備（容器）采用管道連接且中間無閥門隔斷的壓力系統，其兩端設有可與其他系統隔斷的閥門。
3.11
阻火器 flame arrester
阻止火焰在管道內傳播和蔓延的安全防護設備。
3.12
放空阻火器 venting flame arrester
安裝在儲罐的放空管道上，用以防止外部火焰傳入儲罐內，分為管端型和普通型。
管端型放空阻火器為阻爆燃型，其一端與大氣相通，且頂部安裝防風雨帽，以防止灰塵和雨水進入阻火器內部。
普通型放空阻火器分為阻爆燃型和阻爆轟型，其兩端與管道相連，通過下游管道與大氣相通。
3.13
管道阻火器 pipeline flame arrester
安裝在密閉管道系統中，用以防止管道系統一端的火焰蔓延到另一端。分為阻爆燃型和阻爆轟型。
3.14
最大試驗安全間隙 maximum experimental safe gap (MESG)
標準試驗條件下（0.1MPa、20℃），火焰不能通過的最小狹縫寬度（狹縫長為25mm）。
4 安全泄放裝置
4.1 一般規定
4.1.1安裝的安全泄放裝置應能夠防止系統或其中的任一部分發生超壓事故
4.1.2自動控制儀表和事故聯鎖裝置一般不得代替安全泄放裝置作為系統的保護設施，但無法安裝安
全泄放裝置且控制儀表或聯鎖裝置的可靠性不低于安全泄放裝置的情形除外。
4.1.3安裝安全泄放裝置時，應考慮可能產生的超壓因素：
a）設備或管道系統出口關閉；
b）公用工程（冷卻水、電、蒸汽、儀表空氣、惰性氣體和燃料油/氣等）故障；
c）設備和儀表（泵、壓縮機、風機、熱交換器、空冷器系統，以及變送器、控制器，調節閥和報警聯鎖裝置等）故障；
d）液體熱膨脹和流體相變；
e）放熱反應失控；
f）操作人員誤操作；
g）不凝氣體的積聚；
h）易揮發物質進入系統（輕烴或水進入熱油等）；
i）外部火災等。
4.1.4符合下列情況之一者，應設置安全泄放裝置的處所：
a）設計壓力小于外部壓力源的壓力，出口可能被關斷或堵塞的設備和管道系統；
b）出口可能被關斷的容積式泵和壓縮機的出口管道；
c）因冷卻水或回流中斷，或再沸器輸入熱量過多而引起超壓的蒸餾塔頂的氣相管道；
d）因不凝氣體積聚產生超壓的設備和管道系統；
e）加熱爐出口管道中切斷閥或調節閥的上游管道；
f）因兩端切斷閥關閉，受環境溫度、陽光輻射或伴熱影響而產生熱膨脹或汽化的管道系統；
g）放熱反應可能失控的反應器出口處切斷閥上游的管道系統；
h）凝汽式汽輪機的蒸汽出口管道；
i）蒸汽發生器等產汽設備的出口管道；
j）低沸點液體（液化氣等）容器的出口管道；
k) 管程可能破裂的熱交換器低壓側的出口管道；
l) 設計者認為可能產生超壓的其他部位。
4.1.5獨立壓力系統應在適當的位置（設備或管道）設置一個或多個并聯（視泄放量而定）的安全泄放裝置。
4.1.6 安全泄放裝置的相關壓力應按一下規定確定。
4.1.6.1 對于獨立壓力系統中管道上的安全泄放裝置，相關壓力的確定應以系統的設計壓力為基準，且符合以下規定。
a）當安裝一個安全泄放裝置時，安全閥的設定壓力（或爆破片裝置最大標定爆破壓力）應不大于系統設計壓力，且最大泄放壓力應不大于系統設計壓力的10%和20 kPa中的較大者。
b）當安裝多個安全泄放裝置時，至少有一個安全閥的設定壓力（或爆破片裝置最大標定爆破壓力）應不大于系統設計壓力，其余安全閥設定壓力（或爆破片裝置最大標定爆破壓力）不得超過系統設計壓力的5%，且安全閥最大泄放壓力均應不大于系統設計壓力的12%或30 kPa中的較大者。
c）為防止火災事故發生而安裝的安全泄放裝置，且最大泄放壓力應不大于系統設計壓力的16%。
4.1.6.2 對于防止液體管道熱膨脹的安全泄放裝置，安全閥設定壓力（或爆破片裝置最大標定爆破壓力）應不大于管道設計壓力的120%和系統試驗壓力中的較小值，且最大泄放壓力應不超過相應溫度下管道壓力額定值的20%或由壓力產生的管道名義應力不超過材料許用應力值的20%。
4.1.6.3 除上述兩種情況外，在滿足GB/T 20801.3-2006中 4.2.3.1~4.2.3.8要求的條件下，最大泄放壓力應不超過GB/T20801.3-2006中 4.2.3.9和4.2.3.10規定的允許壓力變動范圍。
4.1.6.4 GC1級管道安全閥的設定壓力（或爆破片裝置的最大標定爆破壓力）應不大于管道設計壓力，安全閥的最大泄放壓力應不超過設計壓力的10％。
4.1.7 安全泄放量和最小泄放面積的確定應符合以下規定。
4.1.7.1 安全泄放量應按以下規定確定：
a) 應根據物料平衡和能量平衡，計算各種超壓工況的安全泄放量。
b) 若系統的某個部位有幾種超壓工況，則應分別計算每種超壓工況的安全泄放量，并取其中的最大值為該部位的安全泄放量。
c) 安全泄放量的計算應符合附錄A的規定；附錄A中未規定的其他超壓工況的安全泄放量計算，可參照SY/T l0043—2002、SY/T 10044—2002和HG/T 20570.2—1995的相應規定。
4.1.7.2最小泄放面積應按以下規定確定：
a) 根據安全泄放量、最大泄放壓力、泄放流體溫度、額定泄放系數以及流體的物理性質，計算最小泄放面積。
b) 安全閥和爆破片裝置的最小泄放面積應按本部分附錄A的規定計算。
c) 選用的安全泄放裝置的實際泄放面積應不小于最小泄放面積。
4.1.8安全泄放裝置的進、出口側不得安裝切斷閥。因安全泄放裝置檢測、維修和更換需要安裝的切斷閥應符合下列要求：
a) 切斷閥應是全通徑的，或者其壓力降不會影響安全泄放裝置的正常工作和要求的泄放量。
b) 在全開或關閉位置切斷閥應能被鎖定或鉛封，正常工作時切斷閥應被鎖定或鉛封在全開位置，關閉應在授權人員的監督下進行。
4.1.9 安全泄放裝置的入口管道應滿足以下規定：
a）管徑至少應等于安全泄放裝置的進口尺寸，入口管道的長度應盡可能短。
b）在往復式壓縮機排出口管道上安裝安全泄放裝置時, 脈動阻尼器或孔板的設置應緊靠壓縮機，且脈動阻尼器或孔板至安全泄放裝置的直管段的距離至少應為10倍的管徑。
4.1.10 安全泄放裝置的出口管道應滿足以下規定：
a）泄放至大氣的管道出口應朝向安全地點，泄放管道及其支承應有足夠的強度承受泄放反力。
b) 排放至密閉系統（經泄放總管至排氣筒、火炬系統、收集容器或其他處理系統）的出口管道和泄放總管的背壓應不超過安全泄放裝置允許的最大背壓。
c) 應考慮因低沸點液體(液化氣等)在降壓閃蒸時產生驟冷對管道材料的低溫脆斷影響。
4.2 安全泄放裝置的選用
4.2.1 安全閥的選用應符合一下規定：
a) 安全閥適用于清潔、無顆粒和低黏度的介質；
b) 安全閥應按泄放介質的狀態(氣／汽或液體)選用，并考慮背壓的影響；
c) 安全閥的選用應符合GB 150、GB 12241—2005、GB 12242—2005及GB 12243—2005的
規定。
4.2.2 以下情況應選用爆破片裝置，并應符合GB 150及GB 567的規定。
a) 壓力可能迅速上升的場合；
b) 含有顆粒、易沉淀、易結晶、易聚合、黏度大的介質；
c) 工作壓力很低或很高的場合，且安全閥難以滿足要求；
d) 因強腐蝕性介質而需要使用貴重材料時；
e) 使用溫度較低而影響安全閥的工作性能時;
f) 需要較大的泄放面積；
g) 不允許有泄漏的場合。
4.2.3 以下情況應采用爆破片裝置和安全閥的組合裝置：
a) 串聯使用(爆破片裝置在安全閥入口)
1) 保護安全閥不受工藝介質腐蝕、堵塞或其他不利因素影響；
2) 防止安全閥泄漏；
3) 減少爆破片破裂后的泄放損失；
4) 安全閥的在線檢測。
b) 串聯使用(爆破片裝置在安全閥出口)
保護安全閥不受泄放總管中氣體的腐蝕。
c) 并聯使用
爆破片裝置作為火災工況的輔助安全泄放裝置。
5 阻火器
5.1 阻火器的設置
5.1.1 下列放空或排氣管道上應設置放空阻火器：
a）閃點不大于43℃或物料的最高工作溫度不小于物料閃點的與儲罐直接相連的放空管道（含帶有呼吸閥的放空管道）。確定物料的最高工作溫度時，應考慮環境、陽光照射和加熱裝置失控等因素；
b）可燃氣體在線分析設備的放空總管；
c）進入爆破危險場所的內燃發動機的排氣管道。
5.1.2 符合下列條件之一者應在管道系統的指定位置設置管道阻火器：
a）輸送有可能產生爆燃或爆轟的爆炸性混合氣體的管道（應考慮可能的事故工況），管道阻火器應設置在接受設備的入口處；
b）輸送能自行分解爆炸并引起火焰蔓延的氣體管道（如乙炔），管道阻火器應設置在接受設備的入口或試驗確定的能阻止爆炸的最佳位置處；
c）火炬排放氣進入火炬頭前，應設置阻火器或阻火裝置。
5.2 阻火器的選用規定
5.2.1 選用阻火器時，其最大間隙應不大于介質在操作工況（壓力、溫度、管道尺寸、長度、形狀，及阻火器安裝位置與點火源的距離）下的最大試驗安全間隙（MESG）。爆炸性氣體混合物的技術安全等級應符合GB3836.12—1991的規定，最大試驗安全間隙（MESG）應符合表1的規定。
表1最大試驗安全間隙（MESG）分級表 單位為毫米
級別 最大試驗安全間隙（MESG）
II A ≥0.90
II B 0.90>MESG>0.50
II C ≤0.50
5.2.2 阻火器的選用還應符合GB 13347—1992，GB 5908和SH/T 3413—1999的規定。
6．安全防護
6.1 一般規定
采取安全防護措施時，應考慮以下因素：
a）由流體性質以及操作壓力和操作溫度確定的流體危險性；
b）由管道材料、結構、連接形式及其安全運行經驗確定的管道安全性；
c）管道一旦發生損壞或泄漏，導致流體的泄漏量及其對周圍環境、設備造成的危害程度；
d）管道事故對操作人員、維修人員和一切可能接觸人員的危害程度。
6.2 工廠布置中的安全防護
a）露天化的設備布置應符合以下規定：
1）生產區和居民區之間、裝置之間，建、構筑物之間以及設備之間應保持一定的安全距離；2）裝置內的主要行車道，消防通道以及安全疏散通道的設置應符合國家標準GB50187、GB 50160和GBJ16的規定。
3）應對接近生產裝置的人員予以控制；
4）應設置必要的坡度、排放溝、防火堤和隔堤；
b）可燃、有毒流體應排入封閉系統內，不得直接排入下水道及大氣；
c）密度比環境空氣大的可燃氣體應排入火炬系統，密度比環境空氣小的可燃氣體，在不允許設置火炬及符合衛生標準的情況下，可排入大氣。
d）可燃氣體管道的放空管管口及安全泄放裝置的排放位置應符合GB50160以及GB/T3840的規定；
e ) 架空管道穿過道路、鐵路及人行道等的凈空高度，以及外管廊的管架邊緣至建筑物或其他設施的水平距離應符合GB50160、GBJ16及GB50187的規定，管道與高壓電力線路間交義凈距應符合架空線路相關標準的規定；
f）位于通道、道路和鐵路上方的管道不應安裝閥門、法蘭、螺紋接頭以及帶有填料的補償器等可能發生泄漏的管道組成件；
g）在可通行管溝內不得布置GC1級管道；
