Every few years, the National Fire Protection Association (NFPA) updates a list of more than 300 consensus codes and standards which helps guide safety protocol for everything from food processors to emergency responders.
The large number of regulatory NFPA codes, combined with the sheer size of these documents (NFPA 70, the National Electrical Code, is over 900 pages long), makes it overwhelming to manage NFPA compliance with respect to equipment and operations.
However, as cumbersome as these codes may seem, the risks of not following NFPA standards is both costly and dangerous. To help, we’ve compiled a list of a few specific codes which are commonly used to guide the proper installation of equipment to ensure that your equipment and facility are meeting NFPA standards.
NFPA 70 - Electrical Code and Hazardous Classifications
NFPA 70 is the National Electrical Code (NEC), which covers everything related to the installation of electrical equipment across all industries and all types of buildings, and is enforced in all 50 states.
Due to the size of this code and the comprehensive nature of its scope, we’re focusing specifically on how it handles combustible dust and hazardous location classification.
NFPA 70 defines combustible dust as “dust particles that are 500 microns or smaller” and made of any material that presents a fire or explosion hazard when ignited. This definition is important, because it’s used in a wide variety of other codes as the basis for determining the existence and proper filtration of combustible dust.
Hazardous Location Classification
The NEC defines different classes of hazardous and non-hazardous locations. It’s important to know this hazardous location classification procedure, as it helps determine housekeeping procedures and the proper equipment needed to prevent fire and explosion. These hazardous locations are classified in the following format: class, group, division.
Here’s an example of what this classification may look like:
Hazard classes are determined by the type of fire risk they present:
- Class I locations are hazardous because of flammable or combustible gases and vapors
- Class II locations are hazardous because of combustible dust
- Class III locations are hazardous because of easily ignitable flames
Class II, as an example, is divided into three groups based on the type of dust present:
- Group E locations contain metal dust
- Group F locations contain carbonaceous dusts
- Group G locations contain all other combustible dusts (such as from food, wood or plastic)
Division classes further specify the type of normal operating procedures:
- Division 1 locations, under normal operating conditions, typically have enough combustible dust in the air to pose a risk of a fire or explosion.
- Division 2 locations usually don’t have enough combustible dust in the air under normal operating conditions to pose a risk of a fire or explosion, though certain operational conditions can pose an increased safety risk.
So a total classification may look like Class II, Group E, Division 1, meaning under normal operating conditions, this location has enough metal dust in the air to pose a serious risk for fire and explosion. Fortunately, NFPA 70 provides recommended equipment and protocols for each hazardous location classification to ensure that your equipment is meeting NFPA standards.
NFPA 652 - A New Code on Combustible Dust
NFPA 652 is a new code set in place to help mitigate confusion related to managing combustible dust fires and explosions across different industries, processes and dust types. In the past, it was up to manufacturers and processors to pick the right NFPA code for their industry from an ever growing list, most commonly:
NFPA 61 - Agricultural and food processing facilities
NFPA 484 - Combustible metals
NFPA 654 - General Manufacturing (plastics, pharmaceuticals, etc.)
NFPA 655 - Sulfur
NFPA 664 - Wood processing and woodworking facilities
NFPA 652 was designed to provide general guidance and fill in gaps that were not covered between these different sets of codes. Notably, this standard applies to all facilities and operations that deal with combustible dust—even if not classified as a hazardous location.
Typically when given the option, you should defer to more specific codes, such as NFPA 61, to guide equipment installation, maintenance and operational procedures. However, you should always consult NFPA 654 to ensure that you’re not overlooking a general protocol which has gone unmentioned in industry-specific codes, or to clear up any discrepancies between conflicting sets of rules.
NFPA 68 - Deflagration Venting And Explosion Prevention
NFPA 68 sets the standard on explosion protection via deflagration venting. Essentially, it outlines a set of codes, devices and systems to aide with venting combustion gases, pressures and combustible dust with the ultimate goal of protecting buildings from explosions caused by high temperature and pressure.
When reviewing NFPA 68, there are a few sections to note which can help determine if your current equipment and operating procedures are up to code:
- Section 6.2.2 Provides a formula for calculating vent size in an area where dust is deemed hazardous (see NFPA 70 below).
- Chapter 8 outlines deflagration venting processes for dusts and hybrid mixtures.
- Chapter 11 details installation and maintenance requirements for vent enclosures and systems.
- Annex C discusses a testing procedure for combustible dusts.
- Annex F provides characteristics of combustible dusts observed across common industries.
When In Doubt — Call An Expert
It’s easy to feel overwhelmed when combing through these list of regulations. Just one mistake could mean following improper NFPA procedure and can result in costly mistakes, increased operational risk and increased liability—and we’ve only discussed 3 of the more than 300 NFPA codes currently in existence.
While it’s important to have a strong fundamental understanding of NFPA compliance, it’s equally important to consult an expert to ensure your facility is utilizing the proper equipment and operational procedures. If you’re at all concerned about the effectiveness of your current equipment, or would like to consider new, safer options, contact Clean Air Specialists today to receive advice on making the right purchase for your facility to ensure proper NFPA compliance.