What is the Maximum Allowable Quantity (MAQ) of Hazardous Materials Allowed by Code in a Laboratory or Pilot Plant Area?

We live in a world of acronyms and abbreviations many of which, at least in text messages, defy the author’s interpretation. A common one in pilot plant and laboratory operations is the maximum allowable quantity or MAQ. This is the maximum amount of hazardous materials that are allowed in a building by the building code. If you exceed the MAQ you are (1) unsafe and (2) likely to receive a costly public citation for violating the fire code. The fire department can, in some circumstances, require you to shut down your operations until the problem is corrected.

To understand this issue, you need a bit of code background. The International Building Code (IBC) is the most common code used in almost every US municipality and state. The IBC allows every building a permitted number of control areas as given in Table 414.2.2. These are fire rated rooms or groups of rooms that each have an MAQ attached. The number of control areas allowed vary by floor. Four are allowed on a ground floor, three on the second floor, and less as you go higher. Simultaneously the amount of hazardous materials allowed in each control area (the MAQ) decreases as you go higher. You are allowed 100% of table 307.1 on the ground floor, 75% on the second floor, and less as you go higher.

You are free to define control areas as you desire providing you meet all the code requirements for construction, primarily the fire rating of doors and walls. You can split your ground floor up into 4 equal sized areas or any combination you desire. This is done at the time you apply for the permit to construct the building or when you apply for the permit to modify the building. One permitted you cannot change the control areas without applying for a permit to modify them.

In each control area the amount of hazardous materials has a MAQ by hazardous material category. The categories are given in Table 307.1(1)for physical hazards and 307.1(2) for health hazards. The categories include:

Physical Hazards

·        Combustible dusts

·        Combustible fibers

·        Combustible liquids (NFPA Class II, IIIA, and IIIB)

·        Consumer fireworks

·        Cryogenic flammable liquids

·        Cryogenic inert liquids

·        Cryogenic oxidizing liquids

·        Explosives

·         Flammable gases

·        Flammable liquids (NFPA Class IA, IB, and IC)

·        Flammable solids

·        Organic peroxides

·        Oxidizers

·        Oxidizing gases

·        Pyrophorics

·        Unstable (reactive) materials

·        Water reactive materials

Health Hazards

o  Corrosives

o  Toxic materials

o  Highly toxic materials

The IBC gives fairly detailed definitions for each category. A few are admittedly open to some interpretation (e.g. corrosives) but most are fairly specific so the materials can be categorized off the SDS. The definition for toxic materials, for example, is:

A chemical falling within any of the following categories:

1. A chemical that has a median lethal dose (LD50) of more than 50 milligrams per kilogram, but not more than 500 milligrams per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 grams each.

2. A chemical that has a median lethal dose (LD50) of more than 200 milligrams per kilogram, but not more than 1,000 milligrams per kilogram of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours) with the bare skin of albino rabbits weighing between 2 and 3 kilograms each.

3. A chemical that has a median lethal concentration (LC50) in air of more than 200 parts per million, but not more than 2,000 parts per million by volume of gas or vapor, or more than 2 milligrams per liter but not more than 20 milligrams per liter of mist, fume or dust, when administered by continuous inhalation for 1 hour (or less if death occurs within 1 hour) to albino rats weighing between 200 and 300 grams each.

Table 307.1 Give the MAQ for three separate conditions:

1.      Use in open systems

2.      Use in closed systems

3.      Storage (including use in open and closed systems)

Open system use is normally rare in pilot plants and laboratories except for innocuous materials so the two totals normally of concern are usually the overall MAQ (storage) and use in closed systems. Every category has a specific MAQ with often different values for whether the materials are a solid, liquid, or gas. This base MAQ, in most, but not all cases, may be increased under two conditions. If the entire building is 100% sprinklered then you may double the MAQ. In addition, you may double that (already doubled) figure again (to a total of four times the base) if this last additional amount is all in approved storage. Approved storage is defined as approved storage cabinets, day boxes, gas cabinets, gas rooms or exhausted enclosures or in listed safety cans. Other restrictions for approved storage exist (e.g. the safety cans must be metal and meet a specific UL standard).

Taking a simple example, Table 307.1 allows 30 gallons of a Class IA flammable liquid (Flash point < 73 F, boiling point <100 F) in storage, 30 gallons in use in a closed system and 10 gallons in use in an open system. Effectively, this means you cannot have more than 30 gallons anywhere at any time in a control area. (The storage MAQ which includes all use [both open and closed]).  If the building was 100% sprinklered then the 30 gallons increases to 60 gallons (2 x 30 gallons). An additional 60 gallons may also be in the control area if this amount is in approved storage. For liquids this would usually be a UL or FM approved liquid storage cabinet. So, 120 gallons total would be allowed in the control area.

As long as you stay within the MAQ you are within your permitted limits. If you need to exceed the MAQ then you need to retrofit the control area (and perhaps the entire building) to a high hazard occupancy (H-1, H-2, H-3, H-4, or H-5) depending on what particular classes you are exceeding. High hazard occupancies are more expensive as they require higher wall and door fire ratings, shorter distances to exits, backup power, and numerous other items. You can retrofit (or initially design) just a part of a building to be a high hazard area but the size is limited, typically to 10% of the total area. This is often used to allow a storage room with a higher MAQ.

If your facility was built before about 1996 you may follow a different code with different limits. However any significant modifications, renovations, or additions are quite likely to require yo ubring the area (or even the entire building) into compliance with the latest codes.

For more information on this subject you may want to consider the University of Wisconsin Course on Successful Laboratory Design: Grass Roots, Renovations, and Relocations which will be given virtually on Oct 21-23, 2020. Go to epd.wisc.edu/RA00859 for more information and registration.