Selecting Facility Location to Consider Hazards & Risks

Selecting a facility location is a complex process fraught with many unknowns and concerns that may be difficult due to consider to hazards and risks.

Selecting a facility location is a complex process fraught with many unknowns and concerns that may be difficult to resolve. From the process safety perspective, choosing a location that is not adequately sized or where the impact of process hazards on or from adjacent neighbors has not been determined may result in additional and costly preventive, protective, mitigative, or administrative measures before the processes can be operated. These unanticipated measures may include expensive, maintenance-intensive, and attention-demanding protective systems to counter the potential hazards and risks.

The location selection

team survey potential locations, guiding the team on specific, often critical, information on the new location. In particular, the information helps the location selection team:

• collect critical information necessary to make decisions regarding the location and its size, and
• identify potential issues early in the project associated with each proposed location that may become a concern later in its design and layout, construction, or operation.

Screening Preliminary Hazards

A preliminary hazards screening analysis is used to help identify the potential exposures from the new facility to the surrounding area, or to a new facility from an adjacent hazard. When other hazardous facilities are located near a potential location, their associated risks and impact should be considered when choosing between location. The preliminary hazards analysis described in the following sections provides the foundation for optimizing separation distances between the hazards and their potential receptors - people, environment, and property when reducing the on-site and off-site risks associated with the new or expanded facility.

Fire scenarios may include, but are not limited to:

• A pool fire in a dike or impoundment area, such as from the overflow of a storage tank
• A process unit fire, such as a jet fire
• A full surface area fire in flammable material storage tanks
• A truck or rail car loading rack fire, such as from a hose failure
• A structure fire, and
• A flare during maximum flare system loads, such as when there is a power failure, a loss of cooling water or refrigeration, or an emergency shutdown

Explosion Scenarios:

Explosions can cause damage from blast waves and flying debris, and may result in subsequent fires with thermal radiation hazards, such as fireballs from vented deflagrations, or toxic releases due to other equipment damage from the explosion. Quantitative Risk Analyses (QRA) may be used to evaluate the risks of potential blast overpressures (the consequences) when estimating a safe distances to adjacent process units or facilities.

Toxic Release Scenarios:

Toxic releases usually have the greatest impact to personnel due to potential vapor dispersions, whether from the release of a toxic gas, from the evaporation after a release of a toxic liquid, or from biological toxins. The consequence is based on the quantity released, the material's vaporation properties, the duration of release, the toxicity level, the exposure time of individuals (i.e., people are indoors or outdoors; people are unprotected or have donned proper respiratory PPE). In addition, the extent of the hazard is also dependent on the:

• worst-case inventory that could be lost
• Material's storage conditions
• Weather
• toxic gas plume dispersion

Consider also to credible release scenarios

Releases may occur from, but are not limited to:

• Piping or hose leaks or failures
• Pump seal leaks
• Compressor or turbine failures
• Sample points, vents, drains, plugs left open or broken off
• Vessel overpressure or vacuum resulting in vessel rupture, Utility failures (i.e., potential reverse flow through check valve)
• Process upsets resulting in releases through atmospheric vents or pressure relief systems which vent to the atmosphere

If the footprint of the hazardous consequence from a credible release extends off-site, then the adequacy of the facility's area or the size of its buffer zone will need to be addressed. These potential off-site exposures may affect the permitting process and result in future costly preventive, protective, or administrative measures to compensate for inadequate separation distances between the facility and its surrounding community.

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• 1. Webinar Global Trends: Facility Siting
• 
• 2. CCPS Guidelines for Siting and Layout of Facilities
• 3. Checklist - Identifying the process hazards and risks
• 4. Checklist - Selecting a facility location
• 5. Checklist - Selecting the process unit layout
• 6. Checklist - Selecting the equipment layout
• 7. Guidelines for Siting and Layout of Facilities by coll