API STD 2510-2011 Design and Construction of LPG Installations
9.3.4 Emergency Shutoff Valves
184.108.40.206 Emergency shutoff valves shall be provided in the loading-unloading system for tank cars, trucks, and marine facilities and shall incorporate the following means of closing:
a. Manual shutoff at the installed location.
b. Manual activation from a location accessible during an emergency.
A safety analysis shall be the basis for determining the need for the following:
a. Automatic shutoff in the event of an LPG release.
b. Automatic shutoff through thermal (Þre) actuation.
220.127.116.11 Installation practices for emergency shutoff valves shall include those speciÞed in 18.104.22.168.1 and 22.214.171.124.2.
126.96.36.199.1 When hose or swivel piping is used for liquid or vapor transfer, an emergency shutoff valve shall be installed in the Þxed piping of the transfer system within 20 linear ft of pipe from the end to which the hose or swivel piping is connected. Where the ßow is in one direction only, a check-valve may be used in place of an emergency shutoff valve if the
check valve is installed in a dedicated storage vessel Þll line or vapor return line. When two or more hoses or swivel piping arrangements are used, either an emergency shutoff valve
or a check-valve (for unloading lines only) shall be installed in each leg of the piping.
Note: If check valves are used in place of emergency shutoff valves, the owner/operator should have a program to assure the reliability of these devices.
188.8.131.52.2 The emergency shutoff valves or backßow check valves shall be installed in the Þxed piping so that any break resulting from a pull will occur on the hose or swivel piping
side of the connection while the valves and piping on the plant side of the connection remain intact. This may be accomplished by the use of concrete bulkheads or equivalent
anchorage or by the use of a weakness or shear Þtting. Refer to NPGA Bulletin 128.
API RP 2001-2012 Fire Protection in Refineries
184.108.40.206 Isolation Valves
A key consideration for isolation valves is being able to isolate sections of process to minimize the quantity of hydrocarbons released and prevent influx of additional material from other areas. Isolation valves should be provided at unit boundaries or within process unit areas to isolate equipment during fire situations. Consideration should be given to safe access and the ability to physically operate manually operated valves during fire conditions or in emergency situations. Where possible, battery limit valves should be spaced sufficiently far from process equipment fire hazardous areas to allow safe manual actuation. If located inside fire hazard areas, valves may need to be capable of remote operation.
Isolation valves can also permit blinding for maintenance and inspection. During blinding operations, blinds suitable for equipment-rated pressure should be installed. Isolation valves and drains should be provided for equipment that may be opened or removed during repair operations. See API 553.
220.127.116.11.2 Remotely Operated Valves
Where a review establishes a need, remotely operated shutoff valves (ROSOV) [sometimes used as and called emergency isolation valves (EIV)] should be considered during the PHA and FHA processes. Use of these and other isolation valves should be included in emergency procedures. However, use of automatic (fire or heat actuated) self-closing valves should be used only after a hazard analysis or MOC review to determine whether inadvertent activation may cause undesired consequences. This review should confirm the automatic valve system is inherently safe by a rigorous process safety review since closure of the valve in a nonfire situation or at the wrong time in a fire event may have undesirable consequences, such as causing excessive pressure in a process system or preventing the orderly shutdown sequence of equipment or transfer of product from tanks or vessels during an emergency. The review should include a determination of the safest alternative (“open” or “closed”) on loss of power if ROSOV are used. Discussion of emergency valves (ROEIV, EIV, EBV, ROSOV) can be found in API 553 and UK HES Information Sheet CHIS2.
API 553 -2012 Refinery Valves and Accessories for Control and Safety Instrumented Systems
3.9 emergency block valves EBVs
Emergency block valves are designed to control a hazardous incident. These are valves for emergency isolation and are designed to stop the uncontrolled release of flammable or toxic materials. These valves should be fire-safe, if they are within the fire zone. The valves may be referred to as type A, B, C, and D. Refer to their individual definitions within this section.
3.14 fire zone
This is an area which is unsafe to enter during an emergency situation. The area is considered to be within a 7.6 m (25 ft) radius minimum surrounding the leak source.
3.43 Type A EBV
A manually operated fire-safe block valve installed at the equipment. This type of valve is installed when ignition is not expected in the event of a leak.
3.44 Type B EBV
This fire-safe block valve should be installed at a minimum of 7.6 m (25 ft) from the leak source when ignition is expected. The Type B valve is manually operated and is limited to sizes up to and including DN 200 (8 in.), and pressure classes through ANSI CL300. For reasons of access, the valve should be accessible from ground, or if ground access is not practical, then the valve should be accessible via a platform installed no higher than 4.6 m (15 ft) above grade.
3.45 Type C EBV
The Type C valve is a power-operated Type B valve. The valve should be power-operated if larger than DN 200 (8 in.) or if a pressure class higher than ANSI CL300 is needed. The valve should be installed outside the fire zone a minimum of 7.6 m (25 ft) from the leak source and no higher than 4.6 m (15 ft) above grade. Controls are accessible from the valve location.
3.46 Type D EBV
This is an EBV with remote controls. There is no restriction as to where the valve may be located, but the controls should be a minimum of 12 m (40 ft) from the leak source and should be out of the fire zone. An EBV installed at an elevation greater than 4.6 m (15 ft) above grade will also come under this category. Both the actuator and that portion of the control cable and tubing which is in the fire zone should be fireproofed or designed to operate without failure during fire conditions. Specify that the conduit/tubing/cable supports are required to be fireproofed.