Ignitable liquids in Life Sciences facilities

Nearly all life sciences facilities use ignitable liquids such as solvents, cleaners, adhesives, paints, and fuels. These liquids, which can be either flammable or combustible, ignite through their vapors—not the liquid itself—when mixed with air in the presence of an ignition source. Each liquid has a specific temperature at which it vaporizes and forms flammable mixtures with air. These vapors can travel across surfaces, down stairs, under doors, or along air ducts, reaching areas far from the source.

Ignitable liquids are defined by their boiling point and flash point. The boiling point is the temperature at which a liquid's vapor pressure equals the surrounding atmospheric pressure, causing it to boil and turn into vapor. The flash point is the minimum temperature at which a liquid produces enough vapor to form an ignitable mixture with air, indicating how easily it may ignite. Liquids with higher flash points are less flammable and pose less hazard than those with lower flash points.

An open flame is not always necessary to ignite vapors from flammable liquids. Static electricity or hot surfaces, such as heating elements or warm machinery, can also trigger ignition.

The NFPA (National Fire Protection Association) defines combustible and flammable liquids as follows:

• Combustible liquid: Any liquid with a closed-cup flash point at or above 100°F (37.8°C).
• Flammable liquid: Any liquid with a closed-cup flash point below 100°F (37.8°C).
  
  

Table 1: National Fire Protection Association (NFPA) hazard classifications for flammable and combustible liquids¹

The use of ignitable liquids is common within the life sciences industry, particularly in pharmaceutical manufacturing, as well as in other segments such as biopharmaceutical and medical device manufacturing. Typical applications of ignitable liquids within the life sciences industry include, but are not limited to, the following:

• Laboratory Operations – High Performance Liquid Chromatography (HPLC), dissolution testing, and many quality assurance/quality control tests require the use of various ignitable liquids such as solvents.
  
  
• Cleaning, Drying and Decontamination – Process equipment and finished goods are often cleaned and dried with alcohol or other ignitable liquids. Alcohol is effective at removing small particulate contaminants, displacing water, and evaporating quickly. Additionally, finished medical devices are often sterilized with ethylene oxide (EtO or EO), a sterilant used to eliminate spores and vegetative organisms.
  
  
• Blending and Coating – Pharmaceuticals, whether produced in small or large volumes, may be blended in solvent solutions. The solvent acts as a carrier, enabling chemical binding within drug formulations. Tablets are also commonly coated using solvent- based solutions.
  
  
• Chemical Synthesis – Synthesis of biopharmaceuticals, including cytokines, plasminogen activators, recombinant blood cell or plasma factors, growth factors, fusion proteins, enzymes, receptors, hormones, mAbs, recombinant DNA vaccines, and antisense oligonucleotides, can involve large volumes of solvents for the synthesis and purification.
  
  
• Fermentation – Fermentation processes, used to grow cellular material for vaccines and other biopharmaceutical products, may occur in alcohol solutions, with some cellular materials relying on alcohol as a growth agent.
  
  
• Solvent Based-Batching of Drug Products and API (Active Pharmaceutical Ingredients) – Drug production sometimes involves batching in large reactors with significant volumes of solvents, creating an intensive chemical production facility.
   

Spills involving ignitable liquids, processes heated above the flashpoint, processes under pressure, or vapor releases, can lead to large loss events due to fire or explosion.

There is also the risk of a BLEVE (Boiling Liquid Expanding Vapor Explosion). It occurs when, for example, a drum containing liquid is exposed to fire. The heat causes the liquid inside to vaporize, increasing pressure until the drum ruptures. Once the drum fails, the released liquid vaporizes instantly. If the liquid is ignitable, a large fireball is possible. A BLEVE is also possible even when a vessel is venting as designed.

It is critical to have the correct controls in place to prevent injury or property damage which can result if there is inadequate safety of ignitable liquids. Depending on the type of operation, the required controls will vary. If necessary, a process hazard analysis or another risk assessment framework should be utilized to ensure an accurate understanding of the risks associated with ignitable liquids during normal operations, process upset conditions, and maintenance activities.

Although it may be difficult to identify an alternative chemical, substitution of a safer replacement for an ignitable liquid is the best way to reduce the hazard.

General requirements
 

• Safeguards must be provided for fire and explosion risks as per NFPA 30 or FM 7-14 (Fire Protection for Chemical Plants) and FM 7-32 (Ignitable Liquid Operations).
  
  
• Buildings should be made of non-combustible materials. If combustible building materials are used, they should be replaced with non-combustible materials.
  
  
• Production buildings and storage buildings containing ignitable liquids should be equipped with a suitably designed automatic fire suppression system. For tank farms, deluge systems may be the best option. If foam-based extinguishing systems are in use, consider if fluorine free alternatives should be employed.
  
  
• Eliminate ignition sources such as sparks, flames, hot surfaces, nonapproved wiring, smoking, and static electricity from ignitable liquid areas.
  
  
• Verify that equipment, storage containers, and rooms are rated for ignitable liquids.
  
  
• Ensure proper ventilation with adequate cleaning and maintenance is installed to manage ignitable vapors.
  
  
• Within laboratories and cleanrooms, smaller amounts of ignitable liquids should be stored within cabinets with a minimum 1-hour fire rating. This includes solvent waste, e.g., from HPLC operations.
  
  
• Amount of ignitable liquid in use should be limited to the amount needed for one shift whenever possible.
  
  
• In cleanrooms or biopharma environments, open drains may not be acceptable due to quality requirements. Where closed drains are required in areas with ignitable liquid operations, apply the following guidance as applicable:
  • Minimize the quantities of ignitable liquids present.
  • Provide automatic shutoffs for any ignitable liquid feeds.
  • Provide sealed cleanroom drainage that can be opened automatically.
     
• Pressurized vessels operating at greater than 1 atmosphere or 760 mm Hg should be fitted with a pressure relief or venting system in the form of a cap or rubberized pop-off valve that releases pressure from inside the vessel if certain maximum thresholds are exceeded.
  
  
• Dispensing ignitable liquids should be carefully managed. Proper bonding and grounding should be employed to manage static electricity.
  
  
• Implement employee training and housekeeping procedures to minimize the hazards of ignitable liquids including:
  • Train employees to use the Safety Data Sheet for all ignitable liquids in the workplace.
  • Conduct routine inspections and follow up on deficiencies related to ignitable liquid storage or use.
  • Keep containers closed when not in use.
  • Practice good housekeeping and equipment maintenance.
  • Develop emergency response plans and procedures for ignitable liquids, including shutoffs for ignitable liquids and grounding of dispensing areas and equipment.
     

Outdoor storage
 

• Bulk storage of ignitable liquids should be located well away from key buildings/plant.
  
  
• Where ignitable liquids are supplied to buildings with piped systems:
  • Tank farms and dispensing equipment need to be protected against static charges.
  • The area should be equipped with spill containment.
  • Automatic shut-off of ignitable liquid supply interlocked with fire protection systems should be provided to prevent additional fire load from entering the building and to prevent fire spread throughout the piping system.
  • Manual activation (e.g., switches, levers, buttons) should be provided for ignitable liquid shutoffs and remote opening drains at accessible locations (e.g., near the exit of the room or in the control room). Manual activation systems are secondary systems. They are to be installed in addition to the primary fully automatic systems.

Ignitable liquids often present significant exposures, and it is imperative that companies have a thorough understanding of the risk and required controls to prevent fires, explosions, injuries, and facility contamination. The best protection is to stop a fire from happening in the first place. High level of management controls, with planned preventive maintenance and standard operating procedures can go a long way in this respect.