When starting out on an industrial facility project, there are questions to ask to get the "lay of the land.” One of the first pieces of information to learn is the process description – starting with the incoming raw materials (how they are delivered, stored, and transferred into the batch or continuous process areas of the facility).

The next step of the study of the process is to understand the conditions. Possible hazards stem from how the raw materials are stored and transferred to the manufacturing process, whether the process is a chemical synthesis or simply a mixing process, the temperature and pressure conditions, the duration of the process and what role the operations staff plays. Other factors to consider include whether there is a purification or drying step, how the final product is packaged and stored, and how the finished goods are stored.

It is important to develop an understanding of the unit operations and processes at the facility. This includes a study of process & instrumentation diagrams (P&IDs) as well as narrative process descriptions. A full listing of the hazardous materials – with chemical names, solution concentrations, and container sizes and types – is essential to begin the analysis.


Many codes and standards on the industrial/chemical side contain applicable requirements and valuable information. One of the roles of the FPE is to identify the applicable codes and standards for a specific industrial process and help a facility operator understand how they apply to a certain situation.

The applicable codes for industrial/ chemical facilities contain requirements that connect directly with an understanding of the engineering basis for manufacturing processes and facility design. An existing facility may not be able to implement all of the applicable requirements immediately or even in the first year after a survey or audit. One of the most important tasks when analyzing an industrial facility is to help categorize recommendations into priorities so facility managers can put together a compliance plan. Relevant factors that may influence the compliance plan include the source of the requirement (e.g., code, standard, or underwriting requirement), how the requirement applies to the specific site condition, and recommended options and solutions.

Underwriting requirements also can have a significant impact on the design and operation of an industrial operation. The FM Global datasheets provide requirements for many types of industrial facilities. Underwriting requirements are often a good source of information for a specific hazard or type of industrial process and augment the available codes and standards.

FM Global Datasheets 7-441 and 7-912 contain technical information that can be utilized during the design process. For example, a site layout that includes a chemical process will have specific set-back and separation distance requirements based on the hazard involved. Similarly, a hydrogen storage and dispensing installation can turn to the FM Global recommendations and loss history to address certain hazard concerns, such as exposure to adjacent equipment and protection of process piping systems. Local fire officials often put confidence in underwriting requirements as an aid to their understanding and level of comfort that a complex industrial or chemical process is being adequately reviewed.


There are several factors to consider when designing a fire suppression or detection system in an industrial facility. Many facilities have multiple chemical processes that may each have a different set of hazard criteria. What this means is that the fire suppression and detection system design approaches for adjacent areas in a plant may be different.

It is necessary to be aware of these conditions and take care not to specify a system that may interfere with the effectiveness of a nearby system. Also, one may deal with classes of materials that are incompatible.

For example, a process enclosure containing water-reactive materials may be adjacent to a process that handles pyrophoric gases. The protection schemes for these two processes are quite different. It may be necessary to protect the water-reactive process enclosures with CO2 and simultaneously cool adjacent outdoor pyrophoric-containing equipment with water spray.

The suppression approach and agent should be developed by considering the compatibility of materials in storage and in open or closed process equipment. The Guidelines for Fire Protection in Chemical, Petrochemical, and Hydrocarbon Processing Facilities3 provides information on fire suppression and detection approaches for an industrial site.

The initial step in the evaluation of hydraulic demand for an industrial plant is a hazard analysis of the materials being stored and processed. For water-based fire suppression systems, the hazard analysis provides an estimate of the size of the site fire water loop, as well as any fire pumps and fire water storage tanks.

New technologies in fire detection/ suppression systems provide additional options. There are more gas and flame detectors available than in the past, which enables the fire protection engineer to specify additional methods for detection of gases. Also, for some of the water-reactive chemicals, compatible automatic suppression systems are now available.

Lastly, technologies such as water mist suppression are an addition for facilities that need to contain and treat sprinkler discharge. For example, bio-containment facilities require drainage of sprinkler discharge to a biological "kill” system in the building prior to discharge to the municipal sewer.4

The use of alternate fire suppression agents can require a performance-based analysis that compares the combustible loading in the process area against the performance of the suppression system. Biosafety in Microbiological and Biomedical Laboratories (BMBL)4 includes guidelines for fire protection system design in bio-containment facilities.

The type of product or process condition in the facility will impact the passive and active fire protection systems. For example, a facility that handles pyrophoric gases will likely require a Group H-2 occupancy classification per the International Building Code (IBC).5 The corresponding fire resistance of the building will be impacted. The best suppression method is often to shut off the gas flow via an interlock with a gas and flame detection system.

Raw material solvent distribution and waste collection systems are becoming more commonplace, even in laboratory buildings. Fire protection considerations for such installations include leak detection for transfer piping and organic vapor (LEL) detection at the point of use, as well as static discharge concerns. Considerations that should be addressed include the rate of transfer of the flammable liquid, the propensity to create a static charge, how the static charge could be equalized and dissipated, and what type of pump or inert gas will be used.

A plant with a bulk combustible liquid process may need a foam/water suppression system for both external (monitors) and internal tank protect ion ( foam pourers). The analysis should look at conditions such as the chemical composition and physical properties of the process fluids and the type of fire events that could occur. An understanding of the process chemistry and operating conditions is necessary for sizing and placement of equipment such as external tank monitors, internal nozzles or pourers, and detection devices.


Ventilation systems may be needed for industrial facilities. They provide a controlled working environment for the plant operations staff and minimize the risks to exiting occupants in a spill, release, or fire event. To this end, there are often requirements for dedicated exhaust systems from certain areas, with limitations on the routing of the exhaust to the outdoors. Also, some process areas may need low elevation supply and exhaust to get a complete air change for vapors that are heavier than air.5,6

A fire hazard analysis, such as calculation of flammable vapor concentrations in dispensing and processing areas, can also be performed. The industry standard is to remain below 25% of the lower explosive limit (LEL).5,6,7 However, facility constraints may result in scenarios where concentrations can exceed 25% of the LEL. For example, certain pharmaceutical processes require re-circulation of the room exhaust to maintain area cleanliness levels. Calculation of the vapor concentration with exhaust recirculation can be done and may indicate that 25% of the LEL will be exceeded. This may be acceptable, provided that an explosion prevention method is employed. Possible approaches could include LEL detection interlocked with a purge exhaust rate. Discussions with facility staff are needed, so there is agreement on alarm and interlock points, as well as emergency evacuation and fire department response.

Features such as real-time exhaust monitoring can automatically alert the facility staff to a chemical release or loss of ventilation, initiate their emergency response, and log the data and time to help determine the cause of the event.


One of the most common discussions in industrial facility design concerns the electrical and power systems. There should be a clear agreement on what systems should be on emergency or standby power, and for how long. It may be necessary for both supply and exhaust to be on emergency power to allow for continuous air circulation and to meet door opening force requirements. If only the exhaust is on the emergency generator, the reduction of vapor concentration will be limited, and egress could be difficult.

Industrial plants have many hazardous electrical classification challenges, where equipment may not be procured as Class I or II, Division 1 or 2, and meet the requirements of the National Electrical Code.8 NFPA 4979 and NFPA 49910 are valuable tools that are used to delineate the extent of electrically classified areas. NFPA 49611 is another reference for purged or pressurized enclosures, such as control rooms on the interior of a plant.


Every industrial facility has many special detection devices, alarms, and interlocks. The key is to understand and document how the controls and interlocks will function and what will occur when they are activated. Documentation should address the alarm points, who responds to an alarm, the response procedure, whether the entire facility should be evacuated and, if so, whether workers need to secure processes and hazardous materials prior to leaving the building.

Detection and controls need to correspond to the specific hazard. For example, if one specifies a flame detector and interlocks for hydrogen dispensing, the detector must be capable of seeing the hydrogen flame in the UV/IR spectrum.

As a follow-up to industrial fire protection design work, a site visit is often conducted to review controls and interlocks and verify that they meet the requirements of the initial hazard analysis and specialty code review. It is good practice for the fire protection engineer to witness the acceptance testing of these systems and confirm that they are consistent with the sequence of operations and performance that were recommended.

Jonathan M. Eisenberg is with Rolf Jensen & Associates, Inc.


  1. Property Loss Prevention Data Sheet 7-44, "Spacing of Facilities in Outdoor Chemical Processing Plants,” FM Global, Norwood, MA, 2012.
  2. Property Loss Prevention Data Sheet 7-91, "Hydrogen,” FM Global, Norwood, MA, 2012.
  3. Guidelines for Fire Protection in Chemical, Petrochemical, and Hydrocarbon Processing Facilities, American Institute of Chemical Engineers, New York, 2003.
  4. Biosafety in Microbiological and Biomedical Laboratories, U.S. Department of Health and Human Services, Bethesda, MD, 2009.
  5. International Building Code, International Code Council, Washington, DC, 2012.
  6. International Mechanical Code, International Code Council, Washington, DC, 2012.
  7. NFPA 69, Standard on Explosion Prevention Systems, National Fire Protection Agency, Quincy, MA, 2014
  8. NFPA 70, National Electric Code, National Fire Protection Association, Quincy, MA, 2014.
  9. NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, National Fire Protection Association, Quincy, MA, 2012.
  10. NFPA 499, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, National Fire Protection Association, Quincy, MA, 2013.
  11. NFPA 496, Standard for Purged and Pressurized Enclosures for Electrical Equipment, National Fire Protection Association, Quincy, MA, 2013.