API RP 2001:2019 pdf download
API RP 2001:2019 pdf download.Fire Protection in Refineries.
5.4.3.4 Isolation Valves
5.4.3.4.1 General
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.
5.4.3.4.2 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 non-fire 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 (ROE IV, Ely, EBV, ROSOV) can be found in API 553 and UK HSE Health and Safety Guidance 244.
5.4.3.5 Oil and Gas Piping
Specifications for the construction of oil and gas piping at refineries are contained in ANSI B31 .3. The piping layout should be designed with battery limit valves (API 553) so any major processing area within the refinery can be blocked off in case of fire. This can help prevent the flow of fuel into the fire area and reduce disruption of operations in other areas. Battery limit valves should be installed (5.4.3.4) with provision for good access without personnel exposure and with clearly understood labeling accompanied by relevant emergency response training. Manually operated valves should be evaluated to address the physical effort required to operate them under emergency situations.
During the design stages of a refinery project the process information, such as type of fluids, temperatures, pressures, and flow conditions, must be detailed so that compatible gaskets, materials of pipe construction, line flange classes, and pipe wall thicknesses can be provided for the piping system. Special piping and valving may be needed to address two-phase flow, high-pressure drops, corrosive or erosive fluid properties, or high-velocity flow conditions.
Other special design features of piping that may be of concern and need additional owner/operator review, discussion, and detail include:
a) thermoplastic or plastic lined pipe;
b) double-walled pipe;
c) piping in below-ground service;
d) cathodic protection and grounding features;
e) jacketed or heated piping;
f) preventive maintenance and inspection of piping systems to detect corrosion: under insulation orfireproofing, of plugs, nipples, of supports on piping, and internal;
g) special velocity effects (corrosion, erosion, vibration, noise, water hammer, mechanical, flow-induced vibration, acoustic induced vibration (Refer to API 521) and static electricity:
h) special coatings and insulation;
i) dead-leg potential for water accumulation and freezing or corrosion (see Section 8 and Annex B);
j) piping specification “breaks.”
Consideration should be given to minimization or elimination of unshielded flangeless fittings, gasket-type couplings, or long bolt flanges. When exposed to fire, long bolts can expand and allow flange connections to loosen. Because of historical incidents, many facilities require alternative fasteners on new and revised installations and provide metallic flame impingement shields or insulate long bolts on existing equipment as temporary protection and target them for elimination.
