Electrical Area Classification in Biotech and Manufacturing Facilities

Given these hazards, it is critical to carefully consider the location of flammable materials, the procedures for handling them, the operating temperatures, the safeguards in place, and the relevant regulatory codes. These factors play a vital role in determining appropriate electrical area classifications, which are essential for ensuring facility safety and regulatory compliance.

This two-part series will explore the key considerations and best practices for managing flammable liquids in biotech and pharmaceutical facilities, with a focus on electrical area classification and risk mitigation strategies.

The biotech and pharmaceutical industries routinely handle flammable liquids throughout many stages of production. Whether these substances arrive in small containers or bulk quantities, are transferred into or out of process equipment, transformed chemically during operations, or consumed as part of reactions, their presence introduces a significant risk of fire or explosion.

Given these hazards, it is critical to carefully evaluate where flammable materials are stored and used, how they are handled, the operating temperatures involved, the safeguards in place, and the applicable regulatory requirements. These factors play a vital role in determining appropriate electrical area classifications, which are essential for ensuring both facility safety and regulatory compliance.

This two-part series will explore the key considerations and best practices for managing flammable liquids in biotech and pharmaceutical facilities, with a focus on electrical area classification and risk mitigation strategies.

Reasons for Electrically Classifying Spaces

Electrical and electronic equipment and wiring often present a source of ignition, depending on the components and design. Consider a simple light switch: toggling the switch on or off changes the position of a contact by either closing or opening the circuit. As the contact changes position and the contact surfaces move away from or towards each other, a spark is generated. In the presence of a mixture of air and flammable gas, that spark may ignite the mixture and cause a fire, explosion, or potentially both. Electrical components that operate at elevated surface temperatures pose a similar hazard.

“The National Fire Protection Association (NFPA) 70 National Electrical Code” requires documentation of areas designated as hazardous (classified) or determined to be unclassified. This documentation must be accessible to the authority having jurisdiction, and those authorized to design, install, inspect, maintain, or operate electrical equipment at the location. [Ref. NFPA 70 500.4]

At the start of a project, the design engineer’s goal is to define the electrical area classification for each relevant space. A properly documented electrical area classification clearly identifies the flammable materials present, as well as the class, division, group, temperature code, extent of an area/space, and the basis for determining the classification. This sets the requirements for all electrical and electronic equipment and wiring in the area and serves as a reference for inspection, maintenance activities and ongoing operations.

With the correct electrical and electronic equipment selected, any possible spark and subsequent ignition of flammable vapors is contained to the electrical enclosure. This results in a safer environment for personnel and protects property.

Approach to Developing an Electrical Area Classification

The first step in developing an electrical area classification is to evaluate the process. This includes reviewing Process and Instrumentation Diagrams (P&IDs), equipment layouts, and by discussing the process flow with the process subject matter expert (SME), the client and—when available—process operators.

These focused discussions address what flammables are present, when they are introduced into the process, where they enter/exit the facility throughout the process, why they are being used, and how they are moved through the facility.

Here are important steps to follow.

Step 1: Identify Flammables Present

Classifying an electrical area starts by understanding which flammables are present. Work with the process engineer and client to generate a table of flammable liquids and combustible liquids that are heated above their flash point. For each entry, complete the following data:

• Class I Division Group
• Auto ignition temperature
• Percent lower flammable limit
• Vapor density (Air = 1)
• Temperature class (can be selected by comparing the auto ignition temperature, and the maximum surface temperature in NFPA 70 Table 500.8 (C) (4).)

Complete the identification by working with the process SME and using the table in “National Fire Protection Association (NFPA) 497 4.4: Classification of Class I Combustible Materials.”

Once the flammables are identified, the next steps are to trace each flammable as it enters the facility, moves through the process and exits.

Step 2: Storage of Liquids in Containers

The location of the storage room is key to determining an electrical area classification. It is the first stop in the pathway of liquid flammables delivered from a third-party into a facility. The flammables are supplied in containers, intermediate bulk containers (IBCs) and/or portable tanks and are placed into a storage room where they remain sealed.

A flammable liquid storage room that is totally enclosed within the building requires an electrical area classification of Class I Division 2. When the room is not totally enclosed within the building, having an outside wall, the room is not required to be electrically classified.

For reference purposes, see “NFPA 30 Chapter 9 Storage of Liquids in Containers – General Requirements, 9.12 Electrical Systems.”

Step 3: Flammables Entering

Flammables are often received and stored at the facility before being introduced into the process. When large quantities of flammables are used, it is common to then have them trucked into the facility and unloaded at a tank farm. Smaller quantities ranging from a few gallons to several hundred gallons are supplied in containers.

The received flammables are typically tested to confirm properties before entering the process. This sampling process normally takes place in a fume hood or with the aid of a local spot exhaust system.

Understanding the sampling process provides the basis for determining the extent of the electrical area classification.

Step 4: Flammables Processed

The processing of flammables can result in a waste stream, venting, consumption, or conversion to a non-flammable substance (combustible handled below its flash point).

Begin this step by following the flammable and identifying the point where it is introduced into the process, and the method of introduction. The general terms “closed” and “open” are commonly referred to when describing the handling of flammables in the process.

A closed process may include a hard-piped system directly connected to a vessel where flammable liquids or vapors are not liberated into the surrounding space. The process equipment’s pumps, bleeders, and/or withdrawal fittings become the source points for electrical area classification.

An open process may include removing the cover of a processing vessel that contains a flammable liquid or pouring a flammable liquid directly into another vessel or container. The flammable liquid is normally open to the surrounding space, allowing vapors produced by the liquid to mix with air. The points of flammable liquid exposure become the source points for the electrical area classification.

The process itself may convert the flammable liquid to a non-flammable liquid (combustible liquid, e.g., dilution of ethanol) or even consume the flammable. This conversion or consumption would bring us to the end of following the flammable through the process, because it no longer presents a source point for the electrical area classification.

Step 5: Flammables Exiting

Often there is a waste stream and venting involved that contains or potentially contains flammable liquids and vapors that need to be followed out of the facility.

The waste streams are hard-piped to into a collection tank and the contents of the tank are pumped to a truck and removed from the site. Processing facilities that use smaller quantities may collect the waste streams into containers and further consolidate into drums. The drums are then trucked off site for disposal.

The vent from each piece of processing equipment is often collected to a common process vent header and routed to a collection system or piped to above the roof line for exhausting into the atmosphere. Each of the points (e.g., tanks, vents, pumps) are source points for identifying the electrical area classification.

Step Summary

Each step of the process and each flammable identified must be reviewed to define the extent of the electrical area classification. The conditions of open, closed, indoors, outdoors, air flows, temperature, quantity small/medium/large, pressure low/medium/high, must be considered for developing bubble diagrams that define minimum electrical area classifications.

Incidental Operations

Biotech and pharmaceutical manufacturing operations often include areas where the use, handling, and storage of ignitable liquids is only a limited activity to establish the occupancy classification. These incidental operations do not constitute a hazardous (classified) location.

The most common is the use of Class I and Class II liquids for cleaning and sanitation purposes. “Limited quantities are used to remove manufacturing materials, mold release compounds, and other contaminants not intended to be on the final product. An example would be the use of isopropyl alcohol (IPA), transferred to a cleaning wipe via a plunger-type liquid-dispensing container. The cleaning wipe is then used to remove manufacturing materials not intended to be on the final product.” This is a direct quote from the NFPA 30 18.5.1 and A.18.5.1.

In the next installment of this series, the author will delve into what constitutes “open” and “closed” processes.