GENERAL SPECIFICATION SAFETY

Transcription

1 GENERAL SPECIFICATION SAFETY GS EP SAF 331 Carbon dioxide fixed fire extinguishing systems 03 01/2011 General Revision 02 10/2005 Addition of EP root to document identification 01 10/2003 Change of Group name and logo 00 04/2001 Old TotalFina SP SEC 331 Rev. Date Notes Owner: EP/HSE Managing entity: EP/HSE

2 Contents 1. Scope Purpose Applicability Reference documents Terms and definitions General principles Extinguishing agent Limitation Recommendation CO 2 hazards Safety precautions Distribution system Inspection and maintenance Total flooding system General philosophy Documents and tests Documents Tests Appendix 1 Typical CO 2 semi-modular system Page 2/16

3 1. Scope 1.1 Purpose The purpose of this specification is to define the requirements for the design and installation of carbon dioxide (or CO 2 ) fixed fire extinguishing systems. 1.2 Applicability This specification applies to all CO 2 fixed fire extinguishing systems, in onshore and offshore installations. This specification is not retroactive; it shall apply to new projects and any modifications of existing installations. It does not apply to snuffing of vents. For more details refer to GS EP SAF 262. It does not apply to CO 2 portable extinguishers. For more details refer to GS EP SAF Reference documents The reference documents listed below form an integral part of this General Specification. Unless otherwise stipulated, the applicable version of these documents, including relevant appendices and supplements, is the latest revision published at the EFFECTIVE DATE of the CONTRACT. Standards Reference ISO 3500 Gas cylinders - Seamless steel CO 2 cylinders for fixed fire-fighting installations on ships. ISO 3500/A1 Amendment 1 to standard ISO 3500:2005 ISO 6183 Fire protection equipment - Carbon dioxide extinguishing systems for use on premises- Design and installation Title Professional Documents NFPA 12 Reference Title Standard on Carbon Dioxide Extinguishing Systems Regulations Reference Not applicable Title Page 3/16

4 Codes Reference Not applicable Title Other documents Reference Not applicable Title Total General Specifications Reference GS EP SAF 222 GS EP SAF 262 GS EP SAF 311 GS EP SAF 312 Title Safety rules for turbines, Diesel engines, gas engines and process units in sheltered or enclosed areas Pressure protection relief and hydrocarbon disposal systems Rules for the selection of fire-fighting systems Fire and Gas detection systems 3. Terms and definitions There are three types of statements in this General Specification: shall, should and may. They shall be understood as follows: Shall Is to be understood as mandatory. Any deviation from a shall statement requires a derogation approved by the Company. Should May Is to be understood as strongly recommended to comply with the requirements of the specification. Alternatives shall provide a similar level of protection and this shall be documented. Is used where alternatives are equally acceptable. For the purpose of this specification, the following terms and definitions apply. Automatic operation CO 2 total flooding system Centralized system Isolated (remote) room Operation that does not require any human action. The fire extinguishing system is based on automatic fire detection and CO 2 release (Company). System arranged to discharge carbon dioxide into an enclosed space to achieve the appropriate design concentration (ISO 6183). Fire extinguishing system designed for several zones, with direction valves on the CO 2 network. A common CO 2 storage is used to protect several rooms (Company). Room where personnel are not normally present and where access time for intervention would take more than 5 minutes (Company). Page 4/16

5 These definitions for rooms can be summarized as follows: Time to access Personnel presence < 5 minutes > 5 minutes No routine requirement Unmanned Isolated Routine checks once per day or once per shift Permanent occupancy 50 % of total time per day or 25% of total time per week Not permanently manned Permanently manned Isolated NA Manual operation Not permanently manned room Permanently manned room Semi-modular system Unmanned room (or enclosure) Operation of the CO 2 system requiring human action (Company). Room which does not require the presence of personnel for normal operations, but where entrance for maintenance or control activities is frequent (e.g. switch-room, instrument room). The access is limited to qualified personnel and it is recognized that the intervention is quick (less than 5 minutes) in case of fire alarm (Company). Room which is continuously manned or where personnel are present most of the time, e.g. control room, radio room (Company). Fire extinguishing system designed only for a single zone, with CO 2 storage outside the protected space (Company). Room (or enclosure) where personnel are not normally present and could not enter (except with difficulty) in case of fire, e.g. diesel engine or turbine enclosure (Company). 4. General principles 4.1 Extinguishing agent CO 2 is a colorless, odorless, electrically non conductive inert gas agent used for extinguishing fire by reducing the concentration of oxygen in air to the point where combustion stops. CO 2 extinguishes fire by lowering the oxygen concentration down to approximately 15%, which leads to a minimum effective CO 2 concentration of around 34% in the atmosphere of the premise. Concerning the quality of CO 2 gas, it shall have the properties, as defined in NFPA Limitation CO 2 cannot extinguish fires where the following materials are actively involved in the combustion process: Substances containing their own oxygen supply, such as cellulose nitrate Reactive metals such as sodium, potassium, magnesium and metal hydrides. Page 5/16

6 4.3 Recommendation Carbon dioxide may satisfactorily protect: Electrical equipment: switches, circuit breakers, rotating equipment, electronic equipment Engines using fuel gas (turbine) or flammable liquid fuel (diesel engine) Flammable liquid materials Ordinary combustible materials. CO 2 systems are recommended to protect enclosures (refer to GS EP SAF 311) where no harm to people can be done, such as small cabinets in not permanently manned rooms and machinery enclosures (gas turbine, combustion engine, emergency generator enclosures, diesel fire pump enclosures, refer also to GS EP SAF 222). Fixed and automatic CO 2 extinguishing system for total flooding of these enclosures linked to fire & gas detection may be used. For the existing fixed CO 2 installations in permanently manned or not permanently manned rooms (control room, etc.) and in isolated rooms (technical room), Company requires to upgrade the system to avoid spurious trips and CO 2 release (installation of a three-way valve on the CO 2 bottles system). Refer to section of this specification. 4.4 CO 2 hazards Personnel Considering that CO 2 creates lethal hazards to personnel, its best application is in a total flooding of closed unmanned volumes. The discharge of CO 2 at concentrations required for fire extinguishing (more than 34%) reduces the amount of oxygen and creates serious hazard to personnel. Personnel exposed to CO 2 concentration of more than 10% are drastically disabled. CO 2 effect on personnel can be summarized in Table 1. Table 1: Acute health effects of high concentrations of CO 2 (ISO 6183) Concentration of CO 2 (%) Time Effects 2 Several hours Headache, dyspnoea upon mild exertion 3 1 h Dilation of cerebral blood vessels, increased pulmonary ventilation, and increased oxygen delivery to the tissues 4 5 Within a few min Mild headache, sweating, and dyspnoea at rest 6 Within a few min Less than 16 min Several hours Hearing and visual disturbances Headache and dyspnoea Tremors 7 10 Within a few min 1,5 min to 1 h Unconsciousness or near-unconsciousness Headache, increased heart rate, shortness of breath, dizziness, sweating, and rapid breathing min or more Dizziness, drowsiness, severe muscle twitching, and unconsciousness Less than 1 min Loss on controlled and purposeful activity, unconsciousness, convulsions, coma and death Page 6/16

7 Consideration shall be given to the possibility that personnel could be trapped in, or enter into, an atmosphere made toxic by a CO 2 discharge. Suitable safeguards shall be provided to ensure prompt evacuation, to prevent entry into such atmospheres, and to provide means for fast rescue of any trapped personnel (a minimum time delay of 30 seconds could be set between alarm and CO 2 release). Another hazard is created by the poor visibility prevailing during and after discharge. When a CO 2 extinguishing system is installed in a machinery enclosure, the enclosure shall be considered as a protected space and evacuated prior to CO 2 discharge Electrical and electrostatic hazards CO 2 fire extinguishing systems protecting areas where explosive atmosphere could exist shall utilize metal nozzles, and the entire system shall be properly grounded. In addition, object (such as machinery enclosure) exposed to discharge from CO 2 nozzles shall be grounded to dissipate possible electrostatic charge. CO 2 is a non conductive gas. However, minimum clearances, as defined in NFPA 12, shall be adhered to, between the extinguishing system (piping and nozzles) and any un-enclosed or uninsulated live electrical component. 4.5 Safety precautions The discharge of CO 2 in fire-extinguishing concentration creates serious hazards to personnel, as above described that shall be considered in the design of the system. Carbon dioxide gas is heavier than air and collects in pits, wells, shaft bottoms or other low-lying areas, and can migrate into adjacent places outside the protected space. Visual alarms Five types of visual alarm shall be provided on each upper side of the enclosure: Red fixed: released accomplished, enclosure still flooded with CO 2 Red blinking: release system activated, imminent discharge (30 seconds delay). This function can be achieved with the same visual alarm as above. Amber fixed: system in automatic mode. Amber blinking: system is not functioning because of any discrepancy (for instance such as three-way valve in intermediate position, or to the vent, etc.) This function can be achieved with the same visual alarm as above. Green: system inhibited for operational purposes. Audible alarms One type of audible alarms shall be provided: A two tone electrical alarm to give warning from the early start of operation of CO 2 system (including delay time) Warning signs Warning signs shall be affixed in the areas where discharge of a CO 2 fire extinguishing system could create hazard to personnel. Warning signs shall be simple and evident, written in two Page 7/16

8 languages (English and local) and affixed where they can be clearly seen (on each side of the enclosure). Warning signs are required: In the protected space, highlighting the necessity to evacuate when alarm operates, even if the room or enclosure is not normally manned At the entrance of the protected space, to forbid entering when alarm operates or after discharge until proper ventilation has been achieved In and at entrance of the CO 2 cylinders storage cabinet, to inform of the hazard in case of leakage At every location where manual actuation of the system may be possible to ensure that operator shall not actuate the CO 2 system before having checked that the area is clear of personnel Unexpected/ spurious releases A three-way valve shall be installed in the piping between CO 2 batteries and the enclosure to be protected. This three-way valve shall allow discharging the gas to a safe place (atmosphere). In normal operation this three-way valve shall be addressed to the enclosure to be protected Activation The CO 2 system shall be activated automatically throughout a dedicated fire detection system installed in the enclosure to be protected. A dedicated local panel (see example in Figure 1) shall be installed for each CO 2 system; it shall be installed next to the main access door of the enclosure. The purpose of the local panel is: to show the visual alarms to include the push button allowing the release of CO 2 to include the light s push button test to include the switch button for MANUAL/AUTO selection. The access door shall address an alarm each time the door is open without the CO 2 system being inhibited. The CO 2 discharge is effective only when the system is in AUTO, the fire detectors are activated and the three-way valve is addressed to the enclosure. In case that the three-way valve is addressed to the atmosphere an interlock shall be provided to inhibit the discharge of the CO 2. For MANUAL activation, the three-way valve shall be addressed to the enclosure, and after that, the push button on the local panel shall be activated. The MANUAL/AUTO switch selection button shall not inhibit the CO 2 system. Page 8/16

9 1- Red, yellow and green visual alarms or similar 2- Light test push button. 3- CO 2 release push button. 4- MANUAL/AUTO switch selection button 5- Panel identification tag Figure 1: Automatic System - Local Panel Example Inhibition A key-operated mechanism shall always be installed to inhibit operating of the CO 2 release system for normal operation/ maintenance purposes. The key shall be located outside enclosure, near the entrance. The opening of the door shall provide a specific alarm if the key is not in safe position A local visual alarm (of green color) shall be displayed close to the access when the system is inhibited. The inhibition shall be effective before personnel are allowed to enter the protected space. To make effective this inhibition the three-way valve shall be addressed to the atmosphere and the MANUAL/AUTO switch selection button shall be selected in MANUAL. The access door shall address an alarm each time the door is open without the CO 2 system being inhibited Maintenance override A maintenance override shall be provided on the local control panel. The override of the CO 2 release system shall transmit a remote signal in a permanently manned room (e.g. control room), and also display an alarm on the local control panel Breathing apparatus Wherever fixed CO 2 fire suppression systems are installed, breathing apparatus shall be available and easily reachable for prompt rescue of any trapped personnel CO 2 storage Carbon dioxide systems are semi-modular systems, with high pressure cylinders (67.5 L at 52 barg) grouped in batteries. Centralized systems are not recommended Quantities The amount of CO 2 supplying the system shall be sufficient for protection at the design concentration. The necessary CO 2 concentration shall be achieved in less than 1 minute after Page 9/16

10 the discharge has been initiated. The CO 2 concentrations to be attained after release shall comply with the following recommendations: Type of equipment Concentration% Electrical cabinet 50 Diesel or turbine enclosure 50 50% concentration shall be maintained for at least 20 minutes in electrical cabinet and until engine/ turbine has stopped (with a minimum of 20 minutes) in diesel or turbine enclosure. After the design concentration is reached, the concentration shall be maintained for a substantial period of time, but not less than 20 minutes. A flooding factor of 1.6 kg CO 2 /m 3 shall be used Sparing philosophy As a general rule, a minimum extra capacity of 20% of the amount of CO 2 necessary to extinguish the fire shall be provided for each semi modular unit. This extra capacity shall be permanently connected to the rack of storage cylinders, but the interconnection valve shall be normally closed. For operational reasons (e.g. isolated facility, necessity to re-start up quickly after a CO 2 release, etc.) an extra capacity equal to 100% of the design capacity shall be provided. This extra capacity shall permanently be connected to the CO 2 network but isolated by a normally closed valve, and stored in separate cylinders. A sufficient number of spare cylinders shall also be stored on site Location and control Storage cylinders shall be located as close as possible to the facility they protect, but they shall not be located inside this facility or wherever they may be exposed to fire. Storage cylinders shall preferably be located in open air. Nevertheless they shall not be exposed to the sun radiation. They shall also be protected against severe weather conditions and from mechanical, chemical or other kind of damage. All CO 2 cylinders shall be installed on weighing equipment. A weight loss of not more than 10% of the net content is acceptable. For inspection and maintenance purpose, the location of the CO 2 cylinders shall allow enough space/ clearance around the storage Storage cylinders All fittings on storage cylinders shall be metallic and standardized over the installation. Furthermore, cylinders shall be of the type commonly used in the country so that refilling is achievable locally. Storage cylinders shall be in compliance with ISO 3500 and ISO 3500/A1 and with local regulations applicable for use and transport of pressurized containers and shall be certified by the local certifying authorities. Page 10/16

11 4.6 Distribution system Nozzle Nozzle selection and location shall take into consideration the size and the arrangement of the enclosure to ensure adequate mixing and distribution of CO 2. Nozzles shall be made of stainless steel. In order to prevent foreign material entering the nozzle and obstructing the flow, a "blow off" cover could be installed Piping Special corrosive resistant materials (stainless steel) shall be used for piping. Piping design shall be in compliance with NFPA Inspection and maintenance A Vendor's maintenance procedure shall be provided. This procedure shall provide suitable information for the initial testing (see chapter 6) of the equipment, as well as for periodic inspection and maintenance of the system. These procedures shall include recommendations for at least monthly and yearly checks to assess the system operational condition. They shall address all the routine tests and also a detailed procedure for the yearly inspection of the system to be conducted by competent personnel. 5. Total flooding system 5.1 General philosophy CO 2 total flooding systems shall be semi modular. The general design of the CO 2 system shall be in compliance with NFPA Actuation and interlocks All systems shall be provided with emergency manual control, for use in the event of system failure (automatic operation, normal manual actuation, power, etc.), for instance a manual valve on the cylinder rack. Operation of the CO 2 system shall be interlocked to shutdown the HVAC system and close dampers before discharge. Diesel engines and turbines shall as well be shut down prior to CO 2 release (see also GS EP SAF 222). Unless the persistence of power supply generates additional hazards, power supply shall not be switched off prior to CO 2 discharge. As deenergizing is required, it shall take place before CO 2 release Air tightness Enclosures intended to be protected by CO 2 total flooding shall be as airtight as possible. Particular attention shall be paid to the air inlet/ outlet dampers and air locks. Relative air tightness is necessary for the efficiency of extinguishing, but also for the safety of the personnel standing nearby the protected space; enclosure integrity testing is required as per ISO Page 11/16

12 5.1.3 Fire detection Refer to specification GS EP SAF 312 for the selection of the adequate detection system for automatic operation Instrumentation and control Control system Each extinguishing system shall be controlled by a local control panel, possibly connected to the fire and gas panel or ESD system with the following functions: Initiation of the discharge signal following reception of the automatic fire detection or manual signal (the discharge shall be of the non fail safe design i.e. energize to discharge, with line monitoring) Alarm display and control Time delay (if any) before operation (this function could be replaced by a pneumatic delay system, directly on the CO 2 discharge network) Operation of the interlocks (shutdown of HVAC system, closure of dampers, etc.) Permanent control of the system (supply failure, line monitoring, inhibition, etc.) Operating mode (maintenance override, test mode) Control panel The following information shall be available on the local control panel: System on System fault System in test Pre-discharge alarm (delay running) Discharge signal System manually inhibited. It shall be possible to test and to initiate manually the CO 2 discharge from the panel. A key operated mechanism shall be provided for inhibition. Key operated inhibition mechanism and manual actuation button could also be provided in adequate location (near the door for example), if necessary (e.g. panel and door too far apart) Power source CO 2 systems shall be fed from the essential network. Emergency power (1 charger + 1 set of batteries) shall be provided locally (one supply per building). The required autonomy is 12 hours onshore and 24 hours offshore Ventilation after extinguishing An efficient ventilation system shall be provided to remove CO 2 gas after discharge. This system shall be designed to avoid creating hazardous atmosphere to the personnel. Page 12/16

13 6. Documents and tests 6.1 Documents As a minimum and unless otherwise specified in the contract, the documents to be supplied by Engineering and Supplier shall comply with the following requirements Documents to be supplied by Engineering As a minimum, they shall include: Basic/ preliminary engineering Job specifications P&IDs Preliminary calculation note Logic diagram. Detailed engineering Same as basic but updated Material specifications Material requisitions Equipment data sheets Documents to be provided by Supplier Documents to be supplied upon kick off meeting Preliminary drawings Preliminary dimension and weight for the equipment Preliminary calculation notes. Documents to be supplied for shop acceptance Final drawings approved by Engineering Calculation notes (CO 2 requirement, pressure drop, etc.) Material certificates Equipment data sheets Technical documents for equipment Spare part list Logic diagram Test procedures Cable diagram. Page 13/16

14 The calculation note for the quantity of CO 2 required shall specify concentration, leakage rate of the enclosure, discharge time, design temperature, volume of the area to be protected, theoretical weight of CO 2 required and numbers of cylinders required. If CO 2 systems have to be certified, application files shall be submitted to the competent certifying authorities for agreement. Documents to be supplied upon provisional acceptance Supplier's material and test certificate Pressure and flow-rate report Maintenance and operation manual Test procedure Other relevant detailed test reports. 6.2 Tests Factory test Complete electrical testing and operation of the discharge mechanisms (both automatic and manual) shall be thoroughly checked at the factory and before shipping. This test shall be carried out using a cylinder with air or nitrogen compressed to the maximum extinguishing agent pressure (at maximum temperature). Adequate cylinder opening operation at maximum backpressure shall also be tested Preliminary acceptance test A second test shall be carried out, in operating conditions, with the CO 2 cylinders connected to the network. This test can be conducted wherever it proves convenient: on the site itself, at the integration site or on construction yard. The purpose of this test is to ensure that all piping, nozzles, cylinders and auxiliary devices have been installed in accordance with Vendor's recommendations and approved drawings. The following operating parameters shall be monitored during the test: Effective time delay Operation of visual and audible alarms Operation of interlocks Key-inhibition verification Operation of valves Effective discharge time Measurement and recording of CO 2 concentration and temperature obtained (the gas concentration shall be measured using multi-point recording analyzers). Three-way valves actuation If the installation is controlled by a detection system, a check shall be made to ensure that all signals are correctly transmitted to the control room (not necessarily the central control room) and that the total time for installation actuation is within specification. Page 14/16

15 This test shall be carried out after a satisfactory degree of air tightness of the enclosure has been attained e.g. MCTs installed, doors and windows adjusted, etc. This test shall preferably be carried out before any sensitive electronic equipment is installed in the cabinets. If this is not possible sensitive equipment shall suitably be packed and protected prior to testing. Page 15/16

16 Appendix 1 Appendix 1 Typical CO 2 semi-modular system TO VENT TO CO2 INJECTION NOZZLES PSH Skid manual release X PI PI PI SPARE CO2 CYLINDER SET 100% CAPACITY (when required) SAME WIRING AS DUTY SET CO2 CO2 CO2 XI Alarms in control room Outside room Inside room HS Test HS Maintenance override & T & & or LOCAL PANEL HS Inhibit HS Imminent release Shutdown HVAC HS Auto Local release Close Dampers 1 : Release on going. 2 : Common fault. 3 : Release initiated. 4 : Auto mode. 5 : System overriden. 6 : System on test. FIRE & GAS PANEL. Page 16/16