First Web Edition 2006, Devoted to Engineering Community



Download 2.87 Mb.
Page13/27
Date26.04.2018
Size2.87 Mb.
#46813
1   ...   9   10   11   12   13   14   15   16   ...   27

Purpose


To establish a procedure for systematically identifying all the hazards / risks associated with a task or job and to implement appropriate control measures.

Preventive Maintenance is of utmost significance for such an industrial project that must be kept in full considerations while conceptualizing any scheme. There should be a session of brain storming to find out the causes & solutions for meeting any hazard that may crop in during the operational life of the project. Every risk must be analysed as any miscalculation may lead to intensive fire breakout resulting in losses of billions of dollars as well as severe human loss. There are nowadays several methods given in industrial safety as well as loss prevention methods for the disaster management to prevent such mishaps. The present scope of this book does not allow that to elaborate but informatively included. Let us divide the whole plant industrial area into various zones depending on defined & expected risks. Process area, non-process areas, explosive zone, secured zone, administrative zone, environment unsafe zone etc
Process area can be confined to the real trains zone which is a pure chemical product engineering portion comprising of all vessels involving oil & its storage. This is the only major potential source leading the plant to major fire as well as explosion hazards. All equipments must be made fireproof to the extent possible. The building contained in such zone must be made blast resistant. All arrangements of fire suppression must be made. Proper arrangements must be made for all personnel to use safety devices of all kinds depending of the nature of the hazard so that all users wear preventive dressing / equipment.
Hot as well as cold works areas are defined explicitly for the purpose of preventive adaptation as well as for issuing permits to work within & without plant for the engineering construction works in future. Safe procedure must be defined for such activities. No work should be allowed without granting of such permits. The lost gases or other products or bye products have the potential to spread into the environment air consequently transferring fire possibility a detailed study of that should be made to find a resolution to adopt for suppression measures.
Non process areas should be located distant enough say anything far up to 700 m from the real trains so as the effects are not relocated to this zone that requires only blast resilience structures. Accordingly fire suppression & blast control provisions be applied to the constructions as well as precautionary measures be defined for the personnel. Circulatory areas should be defined in between the process & non-process areas that cannot be definitely delineated but shall carry piping, traffic, roads & many other components of the plant. Accordingly the provisions be given for the disaster management. The most important aspect is the control from fire everywhere for which regular mockups should be conducted. Assembly points be clearly defined at various location that allow following fire alarm to assemble & await further directions from the wardens. Immediate medical attendants & ambulance should be installed. The piping routes must be defined corridors with proper fire protection & guards. No unauthorized person be allowed within the corridors.
Storage area particularly of oil raw material must be provided full protection from firing & explosion viewpoint. This is actually a very high potential source of fire & can cause heavy losses to industry as well as to humans. In case of fire disaster, adequately effective arrangements must be available fully all times to vacate the personnel as soon as possible from the assembly points & further off the plant to safer locations. All classes of fire suppression arrangement must be kept fully functional at the relevant hazard locations clearly defined to the personnel involved & competent fire fighting team made available. Regular training & mock-ups drills must be conducted to keep the involved humans alert to meet any unforeseen.

As far as adverse effects during an occurrence of earthquake are concerned,


Fire Protection

Introduction

The Contractor shall design the fire protection system based on this specification. The fire protection installations shall include all required systems and equipment for the adequate protection of the process and utilities areas. The design and engineering of the fire-fighting systems shall consider the plant layout, the isolation philosophy, the inventories & the critical equipment.



Fire Hazard Analysis study


The design of the fire-fighting systems shall consider the effectiveness of the individual agents. Water Fire extinguishing, exposure protection and cooling, fire intensity control, ignition prevention and prevention of vapor cloud formation. Foam Securing and extinguishing of spill fires in the plant. CO2 gas Fire extinguishing by means of oxygen reduction inside enclosures. Dry Chemical Powder Control and extinguishing of small flammable liquid spill fires and gas-flash fires. Inert gases ‘Inergen’ is one product recognised as environmentally safe to be used for Halon. It is composed of naturally occurring gases Nitrogen, Argon and CO2. Inergen may be used where an electrically non-conductive medium is required. Inergen systems are designed and installed complying NFPA-2001. IG-541 is the name of Inergen in NFPA 2001. The use of Inergen is subject to ‘room integrity overpressure testing’. In manned areas, a qualified pre-alarm status must be in place. Fire proofing, layout, isolation with bunding and catchment shall also considered.

Codes And Standards


It shall be the Contractor's responsibility to be, knowledgeable of the requirements of the relevant International Codes and Standards.

The following latest edition codes and standards to the extent specified herein, form shall be used as a minimum.



National Fire Protection Association (NFPA)

NFPA 10 Portable fire extinguishers

NFPA 11 Low-Expansion Foam

NFPA 11C Mobile foam apparatus

NFPA 12 Carbon Dioxide Extinguishing System

NFPA 13 Installation of Sprinkler System

NFPA 15 Water Spray Fixed Systems

NFPA 20 Installation of Centrifugal Fire Pumps

NFPA 24 Private Fire Mains

NFPA 30 Flammable and Combustible Liquids Code

NFPA 70 National Electric Code

NFPA 72 National Fire Alarm Code

NFPA 850 Electric Generating Plants

NFPA 2001 Clean Agent Fire Extinguishing System


Reference Documents


Project Specifications: Architectural Design Basis, Fireproofing, Electrical Design Guidelines, Power, Control and Earthling Cables, Technical Specifications for Piping Systems, General Piping Process and Utility Design, Layout and Drawing, Design and Installation of Glass-Fibre Reinforced Epoxy and Polyester Piping, Combustion Gas Turbines, Painting, Galvanising, Fire and Gas Detection System, System Cables, CCTV Philosophy, Building Management Systems, Preservation and Export Packing, Safety Equipment Specification , Criticality Rating Calculation Method , Shop Inspection and Test Requirements , Health, Safety and Environmental Philosophy , Project Drawings:

Fire Protection General Plant, Fire Water Diesel Pump


Document Precedence


The Contractor shall notify the Company of any apparent conflict between this specification, the related data sheets, the Codes and Standards and any other specifications noted herein. Resolution and / or interpretation precedence shall be obtained from the Company in writing before proceeding with the design / manufacture. In case of conflict, the order of precedence shall be:

Data Sheet(s), Narrative Specification, Project Specifications and Standards, Industry Codes and Standards, Specification Deviation / Concession Control


The Contractor only through Concession Request format shall seek any technical deviations to this specification and its attachments. Concession requests require Company's review / approval prior to the proposed technical changes being implemented. Technical changes implemented prior to Company approval shall be subject to rejection.


Quality Assurance and Quality Control


Quality Management System shall comply with the applicable requirement of ISO 9001. The purpose of the description herein is to determine factory inspection and testing requirements for fire protection equipment, fire detection equipment, gas detection equipment and alarm system equipment including control panels that shall be listed in project specification. The level of shop inspection and test requirements is defined.

Description

The fire protection and extinguishing system shall include (but not be limited to):

Water supply and distribution system including pumps, mains, hydrants, monitors, hose boxes, hose reel stations and fire point shelters. Water spray systems for process equipment. An automatic CO2 fire suppression system inside gas turbine enclosures. Fire, smoke and gas detection and alarm systems in process areas. Automatic fire suppression systems protecting vital equipment inside buildings. Portable extinguishers (dry chemical powder, carbon dioxide and water) and other movables. General building protection (manual call points, hose reels, and portable fire-extinguishers) Fire Training Facility



The Basis Of Fire Protection


The basic objectives for fire protection is to limit or prevent the escalation of a fire, to avoid risk to life and to minimize material damage until the source of hazard has been isolated or consumed. Fire protection shall mainly be provided by automatically and manually operated fixed-installed systems in conjunction with portable and mobile fire-fighting equipment.



Requirements


Fire prevention and protection measures shall be considered during all stages of plant design.

Process and equipment design shall be assumed as following good engineering practices such as sufficient spacing of equipment, incorporation of emergency shutdown system, relieving system, drainage systems and other special safety considerations for the individual process requirements. Equipment arrangement and distances between fire-hazardous equipment shall be set so that in the event of a fire, the possibilities for escalation are minimized; however, within an operational complex, it is not always feasible to achieve complete separation of equipment. Consequently, additional precautionary measures for fire protection shall be evaluated and submitted for Company approval. This applies particularly to those areas where a chimney effect may occur. For example, a minor fire at a pump may affect overhead equipment causing the fire to rapidly develop. Also, the updraft associated with air-cooled heat exchangers may cause the fire to spread. Design of the fire-fighting system shall be based on the assumption that no fire-fighting equipment and no manpower for fighting fires from outside the plant shall be available in case of a fire. A fire within the plant shall be controlled or extinguished by the plant fire brigade using plant fire engines and plant fire-fighting equipment and devices. The philosophy for designing the fire protection facilities is to utilize the automatic systems and the mobile equipment, which require a minimum number of fire fighters. Access shall be provided for fire fighting particularly for equipment handling flammable liquefied gases or flammable products at or above auto-ignition temperature and the seal / luboil units of rotating equipment. Some equipment shall be protected with water spray systems to remain in operation until the fire brigade arrives to determine the appropriate method of extinguishing attack. The quantity of water required for fire protection shall be based on that is required to control and possibly extinguish one major fire situation at a time under the following conditions: Operation of deluge systems in the zone on fire (or at least 1 monitor), Operation of deluge systems of 2 adjacent zones if (or at least 2 monitors) and 2 hydrants (or 2 monitors).

Note: For large complex units the quantity of water required for fire protection shall be based on the Fire Hazard Analysis study and the QRA, which shall determine the “worst case scenario”.
Detection systems shall be installed in all the relevant areas (process units and buildings) to detect fire, smoke and gas. These shall where required, activate fire protection systems or raise an alarm for action to be taken. Manual call point systems of the 'break glass' type shall also be installed throughout the plant in selected positions to raise an alarm. Indication panels shall be provided in the control room and fire station to enable operators to take appropriate action and to indicate if a fire protection system has been activated. Audible alarms and beacons shall be installed in process units which shall automatically actuate on leakage of gas, or on the outbreak of a fire. Cables for ESD solenoid valves shall be fireproofed and preferably laid in separate trays.
Passive fire protection shall be installed wherever needed on steel supports, towers, vessels, heaters and other process equipment when subjected to severe temperature generated by a liquid hydrocarbon or gas fire.
Positive pressure shall be maintained in the substations and a fire protection clean agent system installed to protect the equipment against damage due to fire. Television cameras with monitoring systems shall be installed to overlook general plant areas enabling operators to take appropriate action when fire, smoke or gas is detected. Around hydrocarbon production facilities, zones or spaces shall be defined in which a gas cloud with gas concentration likely to be above the lower flammability limit (LFL) be present when a major gas or vapor leakage occurs. These zones are called Restricted Zones. The restricted zones concept shall be used to define preventive ignition measures to be taken into account for the items of equipment located inside a restricted zone, e.g. shutting down specified electrical equipment in explosive atmospheres. Hose boxes and fire points containing portable fire-fighting equipment to be located at strategic points adjacent to hazardous areas. Portable fire extinguishers shall be available in those locations where rapid intervention with a relatively small fire extinguisher may prevent a small fire from escalating. The required portable equipment and its location shall be indicated in Fire hazard analysis which must be performed as part of detailed design to address each potential fire hazard

This analysis should consider the following aspects:

The type of combustibles, Fire load of the hazard, Flash points, Ignition sources, Temperature of combustibles, Combustible liquids, Flammable liquids, Exposure to adjacent combustion, Chemicals involved, Detection, alarm, automatic control and monitoring systems process area




The early detection of a developing fire and an early warning to operational and fire-fighting personnel form an important aspect in the basic concept of fire protection.

Fire and gas detection system


The fire and gas detection systems shall be designed complying with Design Specification. The systems shall be used to provide monitoring and control of the plant. Fire and gas detectors are part of fire and gas system. The system shall incorporate data acquisition and printer facilities. The system shall consist of but not be limited to: Fully intelligent system cabinets and their associated field interface cabinets located within the IES (instrument equipment shelters) and various buildings. Each system cabinet shall incorporate a display matrix for the areas it covers. A maintenance console shall provide diagnostic facilities for the system.
Alarm and maintenance printers

There shall be a separate Fire & Gas network connecting the fire and gas alarm system of all buildings and the plant. Necessary fire alarm signals shall be repeated on DCS through serial interface and displayed on control room DCS consoles. All fire alarm systems shall have local panels with display matrix in respective buildings. Alarm lights and audible alarms shall be provided in the plant for the various systems. Lights shall have different colors for different types of alarms. These lights shall be located in the same general areas as the detectors. Alarm colors (lights) provided in the plant area shall be the same on the matrix panel and CRT graphics and should be as follows:



Blue for flammable gas detectors

Red for fire detectors and manual call points

Orange for toxic gas detectors

Maintenance shall be considered for the detector location. Detectors for areas such as compressor shelters should be accessible from crane platforms. Ladders may be used.


Flammable gas detection


Flammable gas detection in open areas

A flammable gas detection system shall be furnished. The signal from the flammable gas detectors shall be sent to Instrument Equipment Shelters (IES) and then to the Control Room (CR).

The CR shall send a signal to a panel in the fire station.

Flammable gas detectors shall alarm at multiple points. The first alarm shall sound at about 10 % of the lower flammability limit (LFL). The sensor system shall be designed to alarm again at 25% of LFL.

When 10 % LFL is reached, each detector shall give:

An individual visual alarm (blue flashing light) on the concerned matrix panel showing the location of gas detection and the system buzzer shall actuate.

The signal shall be sent via the data highway to the fire and gas detection system in the fire station and control room it shall initiate:

An audible and visual alarm in the Control Room, fire station, maintenance workstation

When 25 % LFL is reached, it shall be added:

A common audible alarm and a common visual alarm (blue flashing light) in the concerned process plant area.

An audible and visual alarm in the Control Room, fire station, maintenance workstation & concerned area operator shelter

Flammable gas detectors for hydrocarbon gases shall be located on two criteria

General area coverage detectors shall be as follows:

Between process units handling flammable gases and liquids and process units having open flames.

Around process units handling high-pressure flammable gases (greater than 20 barg). Specific locations based on past industry experience. Detectors shall be provided in the following locations:

on gas compressor seals and

on seals for pumps which handle flammable liquids, inside the entrance to ventilation intakes and on manifolds and hydrocarbon valves to be defined by Company

The type of flammable gas detectors shall be such that concentrate of flammable gas be measured and displayed in the range of 0 to 100 % lower flammability limit (LFL).



Flammable gas detection in the buildings


The buildings are divided in 2 categories as follows:

The process buildings:

Instrument Equipment Shelter (IES))

Electrical Substation (SS)

Operator Maintenance Shelter (ZM)

Sulphur Weigh station Building (WS)

Sulphur Weigh station Truck Driver Building (J2)

Process Chemical Shed (PCS)

Compressor Shelter (CPS)

Smoke room (SM)

Fire Point Shelter (FPS)

Analyser shelter
The non-process buildings:

Laboratory

Storage building

Chemical store

Cooled chemical store

Maintenance building

Fire station

Gate Houses


Process buildings (except analyser shelter)

Three flammable gas detectors shall be provided at the air intake of HVAC system (if any).

A hydrogen (H2) gas detector shall be provided in battery rooms of substations and IES where seal batteries are used. When 10 % of LFL for flammable gas detector or H2 detector is reached, each detector shall give:

An individual visual alarm (bleu flashing light) on the concerned matrix panel showing the location of gas detection.

An audible and visual alarm (blue flashing light) at the entrance and in the concerned building.

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

When 2 out of 3 HC detectors or 1 out of 1 H2 detector reach 25% LFL, the following actions shall be added:

An audible and visual alarm in the Control Room,

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

An audible and visual alarm in the concerned area operator shelter

The ventilation system shall be stopped and dampers closed except for H2 detection in battery room.

Cut-off power supply of Operator maintenance shelter (for flammable gas detection at the air intake of Operator maintenance shelter)

Each H2 detector located inside a battery room shall cut off the battery feeder.


Analyser shelter


Two flammable gas detectors shall be provided at each air intake of HVAC system. One flammable gas detector shall be installed inside the analyser.

When one detector reaches 10% LFL, it shall give: A general audible alarm in the IES associated with the concerned plant area. An individual visual alarm (blue flashing light) on the concerned matrix panel showing the location of gas detection.

A visual alarm in the analyser shelter.

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

Shutdown of sockets located inside Analyzer shelter.
When 25 % of LFL is reached by one detector, the following actions shall be added:

A general audible alarm in the IES associated with the concerned plant area.

An individual visual alarm (blue flashing light) on the concerned matrix panel showing the location of gas detection.

A visual alarm in the analyser shelter.

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

Shutdown of sockets located inside Analyzer shelter.

If 2 out of 2 detectors reach 25% LFL, the following action shall be added:

The ventilation system shall be stopped and dampers closed.

An audible and visual alarm (blue flashing light) in the concerned process area

An audible and visual alarm (blue flashing light) in the concerned process area operator shelter


Non process building


Two flammable gas detectors shall be provided at the air intake of new HVAC system (if any) depending on detection philosophy.

When one detector reaches 10 % of LFL, it shall give:

An individual visual alarm on the concerned control or matrix panel showing the location of gas detection and the system buzzer shall be activated.

An audible and visual (blue flashing light) alarm (if any) at the entrance and in the concerned building.

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

When 2 out of 2 detectors reach 25% LFL, the following actions shall be added:

An indication in the control room.

An indication in the fire station.

An audible and visual alarm in the maintenance workstation

The ventilation system shall be stopped and dampers closed



Flammable gas detection for packages


Three flammable gas detectors shall be located at each air duct inlet of the package.

For the flammable gas detection (distribution and installation) for packages refer to “Instruments furnished with packages” When 10% LFL is reached, each detector shall give:

A general audible alarm in the IES and substations associated with the concerned plant area.

An individual visual alarm (blue flashing light) on the concerned matrix panel.

The signal shall be sent via the data highway to the fire and gas detection system in the fire station and control room to initiate:

An audible and visual alarm in the Control Room,

An audible and visual alarm in the Fire Station.

An audible and visual alarm in the maintenance workstation

When 25% LFL is reached, it shall be added:

An audible and visual alarm in the Control Room,

An audible and visual alarm in the Fire Station.

An audible and visual alarm in the maintenance workstation

When two out of two detectors reach 25% LFL, the following actions shall be added:

A common audible alarm and a common visual alarm (blue flashing light) in the concerned process plant area.

Shutdown of the machine.

Close ventilation dampers and shutdown ventilation fans

Isolate power supply to all equipment not suitable for zone 1

Toxic gas detection


A toxic gas detection system shall be furnished. The signal from the detectors shall be sent to IES and then to the CR. The CR shall send a signal to a panel in the fire station.

H2S gas detection in open areas


H2S detectors shall be located on two criteria:

General coverage detectors shall be as follows:


Between the flares


Inside area handling substantial quantities of H2S and containing operating personnel

Specific location detectors shall be as follows:

On seals of gas compressors handling H2S

On seals of pumps handling fluids containing H2S.

On areas of control valves handling gases that have a significant percentage of H2S.


On sulphur Sumps


Concentrations of H2S gas shall be measured and displayed over the selectable range of 0-50 ppm.

The first alarm point shall be set at 10 parts per million (ppm volume) H2S.

The second alarm shall be set at 20 ppm.

Fire Protection Design Basis


When 10 ppm is reached, each detector shall give:

A general audible alarm in the IES associated with the plant area concerned and operator shelter

An individual visual alarm (orange flashing light) on the concerned matrix panel showing the location of gas detection.

The signal shall be sent via the data highway to the fire and gas detection system in the fire station, control room and maintenance workstation. It shall initiate:

A common audible alarm and a common visual alarm (orange flashing light) in the concerned process plant area.

An audible and visual alarm in the Control Room,

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

When 20 ppm is reached, the following alarms shall be added:

A common audible alarm and a common visual alarm (orange flashing light) in the concerned process plant area.

An audible and visual alarm in the Control Room,

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

H2S Gas Detection In buildings


Process buildings (except analyser shelter)

Two H2S detectors shall be provided at the air intake of HVAC system (if any).

When 10 ppm of H2S is reached, each detector shall give:

A general audible alarm in the IES associated with the concerned building.

An individual visual alarm (orange flashing light) on the concerned matrix panel showing the location of gas detection.

An audible and visual alarm (orange flashing light) at the entrance to and in the concerned building.

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

When 1 out of 2 detectors reach 20 ppm, the following actions shall be added:

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

The ventilation system shall be stopped and dampers closed.


Analyser shelter


One H2S detector shall be provided at each air intake of HVAC system.

In units containing H2S, one H2S detector shall be provided inside analyser shelter.

When one detector reaches 10 ppm, it shall give:

A general audible alarm in the IES associated with the concerned plant area.

An individual visual alarm (orange flashing light) on the concerned matrix panel showing the location of gas detection.

A visual alarm (orange flashing light) in the analyser shelter.

An audible and visual alarm (orange flashing light) in the concerned process area.

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

When one detector reaches 20 ppm, the following actions shall be added:

An audible and visual alarm in the control room.

An audible and visual alarm in the fire station.

An audible and visual alarm in the maintenance workstation

An audible and visual alarm (orange flashing light) in the concerned process area. If the concerned detector is located at HVAC air intake, the ventilation system shall be stopped and dampers closed.



Download 2.87 Mb.

Share with your friends:
1   ...   9   10   11   12   13   14   15   16   ...   27




The database is protected by copyright ©ininet.org 2024
send message

    Main page