Design, engineering key to adequate fire protection
As the search for hydrocarbons extends into deeper and more remote locations with larger production facilities, controlling fires becomes increasingly important for protecting personnel and preserving significant assets. While fire protection standards have been developed to guide facilities design, they serve predominantly as minimums. Correct interpretation of potential hazards of a fire situation and the equipment and systems needed to adequately control these dangers often require the involvement of a formally trained, experienced fire protection engineer.
As a consequence of changing conditions, operating companies are proactive in the application of fire protection during topsides design and integration. Process hazard anal-ysis (PHA) involving formalized analysis procedures plays a significant role in the design of these facilities. Increasingly, they rely on the fire protection engineer resident in the engineering and construction firms to design these sophisticated systems.
The fire protection engineer of today has to be a composite of several engineering disciplines and must be conversant on a broad spectrum of issues and abatement techniques.
A fire protection engineer must be able to discuss fireproofing with the structural engineer, work with architects to plan efficient and viable escape routes, and interact with mechanical and piping engineers to determine fire pump design, sizing, hydraulic pressures, and sequencing. The fire protection engineer must:
* Consult with instrument and automation engineers with respect to ESD, alarm, and detection systems operation
* Interface with electrical engineers to prepare the project’s electrical classification drawings and emergency power systems
* Work with process engineers on process isolation and de-inventory systems and their effect on fire size and duration
* Address the integrity of systems exposed to fire or explosion to lessen the probability of event escalation.
At the pre-conceptual phase of the project, the fire protection engineer assists with the initial technology choices and proposes facilities layout. The engineer assists with the permit application, making certain that applicable regulations and standards are followed. During the front-end engineering design process, he helps in solidifying the layout and interfaces with the operator on formulating technology decisions, specifying equipment that will function throughout the life of the facility without requiring considerable maintenance, developing emergency response plans, and interfacing the safety, fire protection systems, and equipment with these plans.
The fire protection engineer can provide designs for:
* Fire water pumps, controls, and distribution systems
* Fire fighting hardware including monitors, hose, reels, and turnout gear
* Fire systems, including water spray, foam, sprinklers, water mist, CO2, or dry chemicals
* Detection for smoke, flame, and heat
* Gas detection and control devices for detec- ting of toxic or combustible gas or low O2
* Heating, ventilating, and air conditioning and smoke control systems.
Automatic fire protection systems are replacing manual firefighting on offshore installations.
To be effective, fire protection, must be designed with the end use and expectations in mind. One owner may want to protect his asset as well as his people, while another may want to provide protection to allow only the evacuation of the facility and not the protection of the facility itself. One level of protection might be used for a quiescent combustible liquid pool fire, while a different level would be required for a flammable liquid or gas jet fire. A combination of active and passive protection systems may be required to meet the demands of significant fire exposure. The protection must be designed to meet the postulated fire size and duration to be effective, not just meet the code minimums.
North Sea weather conditions, for example, dictate a vastly different criterion for fire protection than do Gulf of Mexico conditions. Giant deepwater platforms and floating facilities, similarly, require a different approach toward fire protection than do smaller, fixed-leg structures.
The technology to fight the fires has not changed significantly in recent years. What has changed, though, is the technology to determine the potential of the fires, providing the correct tools to deal with those fires, and providing the protection that is commensurate with these events.
Many operators today plan their upstream projects using a stage-gate type project management process. Incorporated in the process are value improvement practices that assist in technology selection and constructability issues. Fire protection considerations, to provide the most value to the project, should be incorporated at the early stages of this process as the project goals and operator aspirations are identified. Postponing this involvement can lead to serious miscalculations and under-sizing of fire abatement equipment as the facilities enter the detail design phase, causing schedule delays and cost overruns. With regulations changing continually, reliance on standards from a prior project or using fire protection as-builts may also lead to re-design and construction rework.
Author
Larry Watrous is a fire protection engineer at Mustang Engineering. He has more than 35 years experience in fire protection engineering, training, and project management. He holds a BS degree in Fire Protection Engineering from the University of Maryland.
