SAFETY MANUAL PURGING, VENTING & DRAINING PROCEDURE TABLE OF CONTENTS 1. INTRODUCTION SCOPE DEFINITIONS PROCEDURE...

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1 Page 1 of 11 TABLE OF CONTENTS 1. INTRODUCTION SCOPE DEFINITIONS RESPONSIBILTIES REFERENCES ATTACHMENTS APPENDICES Rev. Issue Date Amendment Description Prepared By Reviewed By Approved By 1 15-Aug-12 Complete Review C. Venkat Haresh/Bart Carl Poldrack 0 1-May-06 First Release Jarvis Olsen Ross Gourlay Next Scheduled Periodic Review: August/2014 Page 1 of 11

2 Page 2 of INTRODUCTION Purging is a common and necessary procedure by which equipment is rendered safe from fire or explosion by preventing an explosive atmosphere developing within equipment or systems. In order to safely prepare equipment for maintenance or for safe operations after maintenance it is critical to oxygen free equipment prior to introducing hydrocarbons and to hydrocarbon free prior to opening to atmosphere. The purging process can involve venting, draining and purging or inerting of equipment containing flammable or combustible materials. The purpose of this procedure is to establish uniformity on venting, draining and purging or inerting of process equipment in a safe and acceptable manner. 2. SCOPE This procedure applies to the venting, draining and purging or inerting of process equipment containing flammable or combustible materials at the Q-Chem manufacturing facilities in Mesaieed and Ras Laffan. This procedure also applies to equipment in corrosive and pyrophoric services. 3. DEFINITIONS Bonding and Grounding is the application of methods to eliminate sparks due to discharge of static electricity when transferring flammable substances from one system or container to another. Cleaning is the removal of liquid or solid residues by flushing, steaming, chemical cleaning or by another recognized method. Combustible Liquid is a liquid that has a flash point above 100 F (37.8 C). Draining is the removal of liquids using a process drain from a vessel or work area to create a safe working condition. Explosive Range is the mixture of fuel and air, at atmospheric pressure, between the LEL and the UEL where the concentration will ignite (flash fire or explosion) when exposed to an ignition source. Flammable Liquid is any liquid that has a flash point below 100 F (37.8 C). Flash Point is the minimum temperature of a liquid at which sufficient vapor is given off to form an ignitable mixture with air, near the surface of the liquid or within a vessel. Flex Hose is a flexible conduit consisting of a tube, reinforcement and an outer cover. A hose is used to convey liquids or gases (media) under pressure. Flex hoses in the context of this procedure are commonly referred to in the plant as flare drop hoses Page 2 of 11

3 Page 3 of 11 Gas Test is a test of an atmosphere using a direct reading instrument to determine oxygen, flammable gas, and/or toxic substance concentrations. A calibrated direct reading instrument must be used for gas testing purposes. Inerting is a means of safeguarding a vessel by reducing the oxygen content to a point where combustion cannot take place inside the vapor space. Inerting gases include a non-flammable and non-reactive gas such as nitrogen or a compatible inert liquid such as water. LEL (Lower Explosive Limit) is the lowest concentration of flammable or combustible vapour in air where a flash will occur in the presence of an ignition source. Concentrations below the LEL will not ignite in the presence of an ignition source. The %LEL is a ratio of the measured vapor concentration of a gas compared with its known LEL. Purging is the removal of flammable/combustible vapours and/or liquids and/or oxygen by displacement with an inert and non-reactive media such as an inert gas (e.g. Nitrogen) or other compatible media such as water or steam. Purge End-Point is the concentration of purge gas in relation to flammable gas (for purging out of service), which renders the mixture safe from the risk of fire or explosion inside the equipment. Purge-end-point is 10% LEL or less. UEL (Upper Explosive Limit) is the highest concentration of flammable or combustible vapour in air where a flash will occur in the presence of an ignition source. Concentrations above the UEL will not ignite in the presence of an ignition source. Venting is the removal of gases or vapours from a vessel or work area to create a safe working atmosphere Methods of Purging and Cleaning Displacement Purging requires the use of water to completely fill a system and displace flammable vapors and oxygen from the system. Water filling is often used to allow welding on tanks which have contained volatile hydrocarbons. While draining the water, vent should be opened to avoid vacuum Steam Cleaning, can volatize residual flammable liquids and remove scale or other undesirable deposits within processing systems. Verify the design condition of the vessel/system (e.g. pressure/temperature/vacuum etc.,) and never exceed the limit. The planning process must ensure that the entire system is heated to a temperature high enough to volatize the contents of the system and prevent condensation of the steam. Using steam to clean and purge can cause vacuum that may result in equipment collapse (implosion) when the steam cools over a period of time. Page 3 of 11

4 Page 4 of 11 Only use steam to purge vessels rated for full vacuum or under the direction and planning of an Operations Specialist. Condensate draining must be done into a closed system as it potentially contains flammable liquids or toxic material Siphon Purging requires the system to be liquid filled and an inert gas is used to displace the liquid as it is drained from the system activities. Care must be taken to ensure the rates of drainage and inert gas introduction match to prevent creation of a suction effect on system which may not be able to resist the implosion forces. This method is effective but cannot deal with the problems of solid or less volatile components within the system that may still emit flammable vapors to create pockets of flammable gasses when the system is opened up or heated Pressure Cycle Purging (Pressure / Depressure-PDP) requires the system to be pressurized with the purge gas and then the entire contents vented to often into a flare header or to atmosphere if the LEL is below 10%. This method reduces the partial pressure of flammable gases within the system and may have to be repeated several times to ensure the mixture within the vessel is below the purge end point. Based on past experience, using nitrogen to do PDP is the most effective method of purging. Nitrogen shall be taken from utility service points for this purpose. For optimum results, at least three PDP cycles are required using the nitrogen pressure-cycle process Sweep-Through Purging requires the purge gas to be introduced into one end of the system and vented at the other, often into a flare header or to atmosphere if the LEL is below 10%. The effectiveness of the purge is dependent upon: the rate of flow of purge gas and the amount of effective mixing the relative density of the purge gas compared to the density of gas being purged the direction of purging dead legs on the system volume of equipment/piping being purged 4.2. Hazards of Purging and Venting Hazards of Purging, Venting and Draining can consist of: Overpressure of a vessel/system Fire and Explosion inside equipment or in atmosphere Flame out of pilots on flare. Page 4 of 11

5 Page 5 of 11 Heat burns during steam cleaning. Vacuum. Spillage of hazardous chemicals. Asphyxiation. Backflow of HC to purging media. Cold brittle fracture of equipment Contaminating the dedicated system Venting to an outside location means either to atmosphere or to a flare header. Purging or venting must not be routed to atmosphere if the LEL is greater than 10%. If purging and venting is routed to atmosphere, the LEL at the venting location must be verified with a portable direct reading gas detector. Always route to a flare header for cases above 10% LEL by use of a flex hose or temporary pipe if permanent flare connection is not provided. When using a flex hose, ensure the hose is inspected and in good condition. Check for leakage if any after lining up. Refer Hose Management Procedure (HSE-SAF-PRO ) for more details. Nitrogen purge shall be released to a safe/elevated location to avoid the risk of asphyxiation Purging into a flare system can cause pilot flame out. Ensure purge gas flow rates are taken into consideration and will not extinguish the flare pilots Overpressure of a vessel / system is a potential hazard when introducing purge gas (Nitrogen). Utility nitrogen header pressure is 8.5 kg/cm² at Q-Chem and 11 kg/cm² at RLOC. A. Do not purge the equipment/piping directly with nitrogen if its design pressure is lower than the nitrogen supply pressure without the following precautions; Use a calibrated pressure regulator to let down the pressure below 50% of the design pressure of the equipment. B. Do not perform purging without any means for monitoring the pressure. If there is no pressure indicator (PI) in the system, install a local gauge in the appropriate location. Refer the section 8.1 for a typical setup. Page 5 of 11

6 Page 6 of 11 C. Do not perform purging if the system is not equipped with a PRV that is set below the system design pressure. If a system contains a Pressure Relief Valve (PRV), ensure it is kept inline. Purge nitrogen pressure should not exceed a pressure setting of relief valve. If a system does not have a PRV, fix the calibrated temporary pressure relieving device (PRV or RD) with proper set pressure. The temporary pressure relieving device release flow should be above the source purge flow. If the system does not have any provisions for temporary pressure relieving device installation, prepare a detailed procedure on how can we avoid over pressurization scenario specific to purging operation and get approval from other area Supervisor or Shift coordinator in Q-Chem and other area supervisor in RLOC. Note: Always use check valve at the process end of the purging system Ethylene Decomposition Avoid rapid pressurization of ethylene filled systems with nitrogen. Rapid introduction of Nitrogen to the system will cause compression of the ethylene in the piping and can trigger a decomposition reaction. Due to the fast reaction rate, PRV protection is not possible for this scenario. Effective prevention is to introduce nitrogen slowly to the piping to reduce compression ratio Purging systems with solids Hydrocarbons entrained in the solids may not be effectively eliminated through Nitrogen purging. Where there are residual solids in a system that is being purged, a team of SMEs shall be convened to evaluate and recommend the most effective method to eliminate the hydrocarbons. (e.g. steaming, chemicals etc.,) The selected method shall be documented either in SOP or as a temporary procedure and communicated to all the affected personnel Purging systems in corrosive or pyrophoric service Purging medium may react with the residual material. Purging method may not thoroughly eliminate or deactivate the residual material Where the system being purged is in corrosive or pyrophoric service, a team of SMEs shall be convened to evaluate and recommend the most effective method to eliminate or deactivate the residual material. Page 6 of 11

7 Page 7 of Gas Monitoring The selected method shall be documented either in SOP or as a temporary procedure and communicated to all the affected personnel It is critical to monitor the purge process to ensure purge limits are reached and verified. To ensure that monitoring results are accurate, follow the requirements of Portable Gas Detector Procedure (HSE-SAF-PRO ) Equipment/System Oxygen Freeing (Specific to pressure cycle purging -PDP) Air (oxygen) must be removed from a system prior to introduction of hydrocarbons to remove any possibility of mixtures existing within the flammable range when the material is introduced Ensure all line breaks and vessel/equipment openings have been boxed up Perform other preliminary tasks to prepare the system for purging in accordance with applicable safe work practices Line up the system to allow complete and thorough purging of the piping, equipment and vessels Ensure that the provisions of are complied with where applicable At the designated purge inlet point, attach a check valve and nitrogen supply hose Open the nitrogen or purge gas into the system and allow the system to pressurize to the designated pressure As the system pressure increases, perform the leak test on the system connections. If any leaks, fix the leak before proceeding When the system reaches the designated pressure, close the nitrogen supply At the vent point, use a portable gas detector to check the oxygen content within the system and record for use as a reference point Open the vent to atmosphere and allow the system to depressure. Do not vent to flare if oxygen is greater than 0.5% in the system. Ensure adequate ventilation at the purge outlet. Where this is not possible, barricade the area and install proper signage When the system is depressurized, initiate the nitrogen pressurization process again. This pressurization / depressurization cycle must be done at least three times. Page 7 of 11

8 Page 8 of Check oxygen concentration after each PDP cycle Once the oxygen content is lower than 0.5%, the system can be purged to the flare if additional purging is required After purging ensure the following: All vents & drains / bleeders are isolated All additional fittings connected for the purging such as check valve, reducers are removed. All vents/drains / bleeders are plugged and capped. Note: To do sweep through purging follow the above steps except sections /4.4.12/ Taking Equipment Out of Service Systems in hydrocarbon service must have the hydrocarbon content reduced to a non-explosive concentration prior to opening the system to atmosphere. An LEL of less than 10% must be achieved and verified using a portable gas meter. Verify design limits (MDMT minimum design metallurgical temperature) of vessels and piping Do not depressure systems with liquid hydrocarbons remaining to avoid chilling equipment below rated design temperature. (i.e. This action may cause autorefrigeration and low-metal temperature situations in which the likelihood of brittle fracture may occur in steel vessels/piping. It is called cold brittle fracture) Prepare the vessel, piping and related equipment for isolation and purging according to the applicable operating procedures and safe work practices. Make sure all sources of hydrocarbons have been isolated from the system to be nitrogen purged. If actuated valves are used as an isolation point in LT&T use the actuated valves guideline as per LT&T procedure HSE-SAF-PRO Open the bleed/flare header hose connection (flare drop) to depressurize the system and remove as much hydrocarbon as possible. Refer Hose Management Procedure (HSE-SAF-PRO ) to select the right type of hose. Depressurise the equipment to the lowest possible pressure (i.e. system pumps are shutdown) Page 8 of 11

9 Page 9 of At the designated inlet purge point, attach a check valve and nitrogen supply hose. Ensure that the provisions of section are complied with where applicable Open the nitrogen into the vessel and allow the system to pressurize to the designated pressure When the system reaches the designated pressure, block in the nitrogen supply and check for leaks Open the vent to flare and allow the system to depressurize When the system is depressurized, initiate the nitrogen pressurization process again. The pressurization / depressurization cycle must be done at least three times. After the third cycle measure the LEL at the vent point with portable gas meter. Once the LEL is below 10%, depressurization can be routed to atmosphere and the system is now considered out of service. Note: Prior to starting work on any equipment/system that has been purged and considered out of service; verify that the LEL readings are still below 10% Prior to working on equipments or systems which are out of service, ensure that all applicable safe work practices (e.g. LT&T, PTW, Blinding, CSE etc.,) are complied with Opening Process Equipment Containing Hydrocarbon to Atmosphere Process equipment shall not be opened to atmosphere until the following conditions exist: Follow the precautions as per section Equipment has been taken out of service as per section 4.5 Appropriate energy isolations have been completed and verified as per applicable safe work practices (e.g. LT&T, Blinding etc.) 4.7. Draining Hydrocarbons (Flammable Liquids) into Drums or other Open Containers Draining hydrocarbons in to drums or other open containers is considered as a high risk activity. Evaluate the need and prepare a Job Safety Analysis (JSA) in advance of the draining operation Containers shall be compatible with the material being drained and labelled Follow the guidelines for Grounding/Bonding during draining of flammable hydrocarbons (HSE-SAF-GLN ) Page 9 of 11

10 Page 10 of All hot work and other known ignition sources shall be suspended within a 15 meter radius (minimum) of the draining operation Continuous gas monitoring must occur within a 15 meter radius (minimum) and LEL readings must never exceed 10% at any time. JSA must address actions to be taken if LEL crosses above 10% any time Training Computer Based Training (CBT) shall be provided to affected personnel as per the Global Training Matrix. 5. RESPONSIBILTIES 5.1. Safety Section Update and maintain the procedure and computer based training (CBT) current 5.2. Production Department Ensure gas testing is done in accordance with this Safety Procedure and the Portable Gas Detector Procedure Identify the requirement and ensure the right types of containers which are compatible to the service are available. (as applicable) Identify the requirement and ensure the certified pressure regulators/pressure gauges are available. (as applicable) Identify the requirement and ensure the calibrated temporary pressure relieving devices (PRV or RD) are available. (as applicable) Maintain the availability of certified hoses for different applications Ensure grounding and bonding cables/straps are available and used as per the requirements of this Safety Procedure Training section: Ensure affected plant personnel are adequately trained on this procedure. 6. REFERENCES HSE-SAF-PRO Confined Space Entry Procedure HSE-SAF-PRO Portable Gas Detector Procedure HSE-SAF-PRO Hose Management Procedure HSE-SAF-PRO Lockout, tagout and try (LT&T) procedure HSE-SAF-GLN Grounding/Bonding during draining of flammable hydrocarbons Page 10 of 11

11 Page 11 of ATTACHMENTS None 8. APPENDICES 8.1. Pressure regulator and pressure gauge assembly for low pressure system purging Page 11 of 11