This is the first of a two-part series to help grain and feed processors understand the new actions proposed by NFPA 652, the latest. The second part of the series will examine the spectrum of dust control options available, and evaluate the strengths and weaknesses of each alternative.

In all situations, it is always dangerous if you don’t know what you don’t know. This is especially true of combustible dust because in this case, ignorance is not bliss. In fact, it is deadly.

The risks from fugitive combustible dust continue to remain high for grain processors. Fugitive dust accumulates, forming a combustible cloud that results in explosions that destroy facilities and/or injure or kill employees. Unfortunately, this is not an isolated event. The latest statistics on combustible dust explosions is chilling. Over a 25-year period in the US from 1980-2005, there have been: 281 combustible dust incidents, 718 injuries and 119 deaths. From 2008-2012 there have been another 50 accidents reported.

Whilst these dust incidents occur throughout many industries, feed and grain is one of the leading industries experiencing explosions.

In February of this year, an explosion at the Rockmart Feed Mill

in Atlanta, Georgia killed one person and injured five others. The tragic irony of this incident is that the plant had been reviewed by OSHA in 2013 after a small dust explosion, and had subsequent annual on-site inspections.

Nevertheless, feed dust continued to accumulate between the inspections and consequently caused the disastrous explosion. A witness described to WSB-TV in Atlanta, that the sound was as loud as a “sonic boom or an earthquake.”

Similarly, in June 2016, OSHA fined High Country Elevators Inc. US$51,920 for several issues including combustible dust accumulation above 1/8.

These are just two examples of unnecessary tragedy and expense, as a result of a lack of collective knowledge or concern for compliance – or perhaps both.

Regulatory agencies have responded with issuing higher fines and new standards. No one wants more accidents. But there remains a gap in knowledge and I am writing to fill that gap.

NFPA releases new standards In August 2015, the National Fire Protection Association

(NFPA) published a new standard on combustible dust: NFPA 652. It is designed to supply unifying standards and principles across industries.

Currently, the draft of NFPA 652 is in review for possible edits. Although a second revision is scheduled to be released in January

NEW REGULATORY STANDARDS AND PRACTICAL SOLUTIONS

by W Brad Carr, President, SonicAire, USA

From 1980-2005, an estimated 119 deaths have occurred in the US alone, as a result of combustible dust explosions, with feed and grain as one of the leading industries experiencing explosions

PART 1

56 | October 2016 - Milling and Grain

F

2018, it is wise for us to consider the changes required in the current version since it has been issued.

Therefore, what follows are the highlights of changes dictated by NFPA 652 issues so grain processors can take action to best protect their businesses and employees. There are significant changes to processes that the grain industry must be aware of and respond to.

Scope of standardNFPA 652 defines its scope as the following: “This standard

shall provide the basic principles of and requirements for identifying and managing the fire and explosion hazards of combustible dust and particulate solids.”

In essence, it sets the standards that are fundamental requirements for all industries with combustible dust hazards. NFPA 654 was once considered the umbrella standard for all industries not covered by other NFPA standards for specific industries.

The new NFPA 652 sets a baseline for all industries. In addition, NFPA 652 concentrates more on specific management and procedural requirements to mitigate fire and explosions from combustible dust. Together, NFPA 652 and the other industry-specific standards provide a comprehensive framework for managing combustible dust hazards.

Combustible dust standardsDuring the development of NFPA

652, (Exponent, 8.11.15) there was debate over how to interact with existing commodity-specific combustible dust standards, when those standards contain differing requirements. To accommodate those differences, NFPA 652 contains a conflict section on which standards take precedence when there is a discrepancy in requirements.

Overall, NFPA 652 emphasizes the need to evaluate and manage - not just measure. The main changes lie in the need for a Dust Hazard Analysis (DHA) and a Management of Change (MOC) plan.

How to develop an actionable DHA

The Dust Hazard Analysis is one of the biggest changes in required activities for feed and grain processors. In fact, a DHA is required for all companies that generate, process, handle or store combustible dusts or particulate solids. It is required and is permitted to be phased in no later than three years from the effective date of the standard and is applied retroactively.

Steps to designing a helpful DHA:Step 1: Identify all processes connected with combustible dust.

List process lines where dust could exist. Identify all pieces of equipment, such as bins, silos, tanks, bucket elevators, sifters, dryers, ovens, conveys, screen augers and classifiers.

"The risks from fugitive combustible dust continue to remain high for grain processors. Fugitive dust accumulates, forming a combustible cloud that results in explosions that destroy facilities and/or

injure or kill employees "

Milling and Grain - October 2016 | 57

F

Step 2: Identify locations where dust can accumulate. This means you have to inspect all areas where dust exists, and identify the level of accumulation. You must pay particular attention to overhead structures such as piles, joists, beams and ductwork. You also have to examine drop ceilings and any area where dust potentially could be released in abnormal conditions.

Step 3: Determine your ignition sources. This can come from anywhere, but pay attention to process equipment, smoking, static electricity, forklifts, welding or other high temperature work, friction, electrical sparks or arching, radiant heat, and open flames.

Step 4: Quantify the risk. Evaluate the deflagration and explosion potential for each area and piece of equipment. Determine the severity of risk for employees and processes. If the

area/equipment is deemed hazardous, identify performance-based or prescriptive methods for remediation.

Step 5: Examine and evaluate current safety measures. This includes housekeeping, suppression, isolation, venting, facility-design and equipment selection.

How to design a MOCA management of change (MOC) plan is now required for

certain changes made in any facility. Logically, the plan will vary according to the specific change identified.

What is needed is a written MOC to comply with NFPA 652 recommendations. You must have one on hand if there are any deviations from the original DHA.

Other NFPA 652 noteworthy changes• You cannot just look at the accumulation tolerances identified

in NFPA 652 alone. Instead, you have to consider 652 and the industry-specific standard for dust level accumulations

• Each plant must have its own threshold level of allowable dust accumulations, set by owner or management. From there, housekeeping methods will be developed, with appropriate documentation

• Operating equipment within an explosion hazard location must be isolated

• All buildings or areas with a dust deflagration hazard need

to be protected by either performance-based or prescriptive methods

• Overhead fans to limit dust accumulation have been identified specifically as a viable housekeeping solution

• Engineering design controls are preferable for difficult to clean areas (A.8.4.2.6.1)

What is new with OSHA? The good intentions of NFPA do not necessarily translate into

good practice. Whilst all of these standards are developed by experts in the field, they are are only voluntary.

OSHA regulations give legal teeth to these standards. Since 2006, the Chemical Safety Board (CSB) has been pushing OSHA to announce and enforce a general industry standard for

combustible dust. This push occurred after the CSB study that found there were so many dust-related incidents from 1980-2005.

At the beginning of the Obama administration, it looked as if OSHA was going to do just that. They were focusing on regulations that were as strong as when they began to implement a National Emphasis Program (NEP) in 2008, a program that encouraged Congress to develop two bills (HR5522 and HR 691) to regulate and enforce these standards. Both bills died slow deaths in committee.

Bloomberg BNA reported (1.11.16) that OSHA is not likely to push for a comprehensive dust standard based on NFPA 652. Their officials have not attended NFPA meetings in the last 18 months.

However, OSHA is still enforcing the industry-specific standards for combustible dust hazards. In November 2015, federal provisions were made for OSHA to increase its penalty fines; some industry experts expect it to increase by as much as 82 percent.

But OSHA now allows the density of dust to be considered when inspecting for accumulation. Because not all dust is created as equal, the density

of dust has an allowable accumulation that is potentially higher (<1”). To use a higher metric, plant managers must send their dust to a laboratory for bulk density testing. The higher the number of the dust’s bulk density, the lower the allowable accumulation becomes.

However, even with these calculations, it is extremely rare to come across a bulk density number of less than 3lbs/ftˆ3. This means that most industries remain unaffected by this new measurement standard.

The bottom line with OSHA in the real world is this: Keep fugitive dust accumulations as low as physically possible. I know I don’t want to find myself arguing about the density of my plant’s dust with an OSHA inspector. And let’s face it, we all need to do what we can to keep danger out of the workplace wherever possible.

So what do we do now?The hard cold reality is that the risks still exist regardless of the

government’s action or inaction. Clearly therefore, we have to implement solutions that could

provide the safest solution that makes the most business sense. In order to do that, we need to know what is available, and evaluate the strengths and weaknesses of each option.

I will address this in Part 2 of this Series in the next issue of Milling and Grain magazine.

This graph shows the breakdown according to Occupational Safety and Health Administration Combustible (OSHA) Dust National Emphasis Program, 3-10-08

FOOD PRODUCTS 24%

LUMBAR & WOOD PRODUCTS 15%

CHEMICAL MANUFACTURING 12%

PRIMARY METAL INDUSTRIES 8%

RUBBER & PLASTIC PRODUCTS 8%

ELECTRIC SERVICES 8%

OTHER 7%

FABRICATED METAL PRODUCTS 7%

EQUIPMENT MANUFACTURING 7%

FURNITURE & FIXTURES 4%

Figure 1: Industries involved in dust related incidents

58 | October 2016 - Milling and Grain

F