The NFPA Standard for Grain Elevators
Whatever the numbers, insurance companies have worried about grain elevators since a series of big explosions in 1919 and 1921. Responding to calls for an industrywide standard on grain elevator safety, NFPA appointed a Committee on Dust Control in Grain Elevators. Insurance interests have been major participants in NFPA's subsequent efforts. The committee, lacking sufficient information on certain aspects of the explosion problem, hired Underwriters Labs (another organization created by the insurance industry) to investigate methods of controlling floating dust in terminal grain elevators.
The results of the UL study formed the basis for the dust-control provisions in the early versions of the standard, which also contains general operation and design provisions. It has been revised at least five times since then, although many of the provisions in the most recent version can be traced back to 1953. The most significant changes were in 1970, when NFPA added country elevators (formerly governed by a separate standard) to the scope of the standard, and in 1980, when NFPA responded to the threat of imminent government regulation by strengthening the ignition-control requirements for bucket elevators.
The revision process began again with a meeting in July 1985 of the Technical Committee on Agricultural Dusts, and a revised version of NFPA 61B (hereinafter "61B") was adopted the following year.
The Agricultural Dusts committee, chaired for the past fifteen years by a representative of Continental Grain, has approximately two dozen members. Twelve to fifteen attend formal committee meetings, but all actions are subject to letter ballot by the full committee. The largest-segment of committee membership comes from the insurance industry—Industrial Risk Insurers, the Mill Mutuals, the Insurance Services Office of Nebraska, Kemper Insurance Co., and Factory Mutual Research Corp. are each represented. Two other organizations related to the insurance industry, UL and Johnson & Higgins (a brokerage firm), are represented on the committee along with Cargill, the country's largest grain company, and two major grain processors (Kellogg Co. and General Foods). Other representatives include those of a fumigant company, a fire equipment manufacturer, a manufacturer of grain-handling equipment, and several academics. Conspicuously absent from the committee roster is a representative from OSHA. "It wasn't for lack of trying," notes an NFPA staff member. Neither was it always this way. OSHA's policy on participating in private standards-setting activities has varied by administration and by issue.
Certain provisions in 61B have been a source of repeated debate over the years. Such issues, according to the current committee chairman, are brought up practically every time 61B is revised. Some of these largely technical issues are discussed below. But 61B is probably better known for what it does not cover than for what it does. Some provisions, including those on housekeeping, are so general that the standard quite literally requires nothing in particular. Additionally, owing to the retroactivity clause, most provisions apply only to new facilities, even though older facilities actually pose the most serious hazards.
In its present form, 61B is a remarkably compact regulation, devoting no more than a page or two apiece to chapters on construction requirements, equipment, and dust control. Most provisions are as general as they are brief. "Extraneous material that would contribute to a fire hazard shall be removed from the commodity before it enters the [grain] dryer." "Boot sections [of the elevator leg] shall be provided with adequate doors for cleanout of the entire boot and for inspection of the boot pulley and leg belt."
NFPA 61B avoids almost all design details. The complex topic of
explosion venting, for example, is addressed by reference to a separate NFPA venting guide that committee members agree is not particularly applicable to grain-handling facilities. Similarly, dust-control systems are mentioned, but there are no performance requirements or construction specifications. In contrast, the National Academy of Sciences has published a 116-page guide to designing pneumatic dust-control systems.
Housekeeping: A Gentlemen's Agreement
The most significant provision in 61B is the basic housekeeping requirement. Unlike the standard later adopted by OSHA, which contains specific action levels and alternatives for dust control, 61B dispenses with the topic by stating simply that "dust shall be removed concurrently with operations." This language has been known to provoke a good laugh from Agricultural Dusts committee members pressed to explain what it really means.
Whatever it means, the provision is not enforceable. OSHA learned that when it tried to use 61B in support of citations issued after the 1977 explosions. The commission that reviews OSHA citations was unwilling to rely on such an ambiguous provisions. In actuality, the housekeeping provision is not a "requirement" at all. It is more of a gentlemen's agreement to recognize the problem but leave its solution entirely to the individual operator. "I think that you have to consider that people are going to be reasonable and rational about applying this," explained a Continental Grain representative at an OSHA hearing.
Whether a more specific requirement would be desirable is the subject of considerable controversy. Leaving that question aside for the moment, the lack of specificity of the housekeeping requirement in 61B is not adequately justified by the reasons most commonly offered in its defense. "If someone can tell us how to be more specific and be scientifically logical" in establishing dust-control requirements, explains an Agricultural Dusts committee member from a major grain company, "we would buy it." Indeed, there is no way to do so—short of banning grain dust—if "scientific logic" demands total safety. Research sponsored by the NGFA indicates that a dust layer as thin as one-hundredth of an inch can propagate an explosion. The NGFA has been accused by its detractors of conducting this research precisely to bolster the "scientific" argument against any standard. But there rarely is a strong
scientific basis for resolving complex problems involving the trade-off between cost and safety. If this call for greater scientific certainty applied equally to all standards-setting, it would largely paralyze the effort. There are too many variables interacting and changing over time to expect anything resembling scientific certainty for each one.
Guesses, commonsense judgments, and just plain arbitrary numbers adorn public and private standards alike. They have to. NFPA 61B is no exception. The requirement that grain driers be cleaned every 168 hours, for example, is not scientifically logical. As it turns out, 168 was chosen because that is how many hours there are in a week—a measure no more scientific than Continental Grain's policy of cleaning them every 48 hours. Limiting the temperature of hot pipes to 160° F, prohibiting more than 25 percent of a roof from being plastic panel, and suggesting that motor-driven equipment be cleaned at one-hour intervals during operations are further examples of provisions in 61B that are equally susceptible to the charge of scientific infirmity. In each case, the number is an admittedly arbitrary one, based on the consensus of committee members as to what constitutes a reasonable requirement.
In fact, scientific uncertainty did not prevent Continental Grain or the Factory Mutual Corporation from incorporating an "action level" of one-eight of an inch of layered dust into their own in-house standards for housekeeping. So why does the NFPA Agricultural Dusts committee demand more of science? One possible reason is that the dust-control problem is more complicated than most issues. Hot pipes present similar hazards under a variety of circumstances; grain dust does not. Dust hazards depend, to some degree, on virtually every aspect of a grain-handling facility, including the product it handles, its sales and operation patterns, the general layout and date of design, and the effectiveness of existing dust-control equipment. In short, some facilities have much less need or ability than others to conduct housekeeping. The image of the "small country elevator"—a mom-and-pop operation with no hired hands, but a line of anxious farmers waiting to unload their grain before it starts raining—is often evoked in this line of argument. Some country elevators have little need for dust control because they have low throughput and no enclosed bucket elevators. Others, it is argued, lack the resources to purchase dust collection systems or hire additional labor. The appropriate action level, if there is such a thing, varies significantly by facility, and the small ones should, the argument continues, be spared the regulatory rod entirely.
This position on dust control contradicts the position taken else-
where in 61B. The Agricultural Dusts committee has gone on record several times against the notion that differences in facilities render a general standard inappropriate. Separate NFPA standards for country elevators were combined with those for other grain-handling facilities in 1973, when the committee decided that "a distinction between types of grain elevators on the basis of capacity or shipping or receiving media is no longer practical." Similarly, a committee member argued in July 1985 that motion switches should not be mandated on all bucket elevator legs because some country elevators "do not realistically need them." The committee rejected the argument on the grounds that motion switches were generally a good idea and it would be impossible to identify in a standard those situations in which they are not necessary. The same could be said about dust-control requirements. "Facilities vary," notes a former USDA investigator, "but the hazard scenarios are the same."
The Unspoken Arguments: Liability and Retroactivity
So why is the housekeeping provision in 61B so vague? Two factors other than the limitations of science and the diversity of facilities are at play. One is specific to this issue, the other indicative of a larger force affecting the development of private safety standards. There is an unspoken belief that good housekeeping simply is not the answer. To some, it is a matter of practicality. It would require excessive effort, the argument goes, to keep an elevator clean enough to prevent explosions. "There is no such thing as a clean elevator," quipped one trade association representative. Perhaps the strongest explanation is that a specific housekeeping provision could be legal dynamite. Industry has learned that voluntary standards can and will be used against you in a court of law. Most explosions lead to litigation. According to a retired Cargill executive who testifies in such lawsuits, 61B and a host of related standards are raised in almost every case. The stakes can be very high. The two largest explosions in 1977 resulted in settlements of approximately $25 million each, and a jury recently applied the bane of the tort law—punitive damages—for the first time in a grain elevator case. The vaguer 61B is on housekeeping, the less powerful a weapon it would be after an explosion. Some of the vagueness, then, is simply an attempt to make the standard liability-proof. The ill-fated OSHA citations that relied on 61B are testimony to the effectiveness of this strategy.
Success, in this context, breeds more generalities. Substituting what Agricultural Dusts committee members refer to as "motherhood statements" for specific provisions is an increasing trend with 61B. Space heaters shall be located in "suitable places." Fire extinguishers shall be located in "strategic" places. A proposal that all bearings be properly maintained in accordance with the manufacturer's specifications was rejected by the committee in 1985 in favor of a requirement that "all bearings shall be properly maintained." ("Let's see what a lawyer can do with that one!" mused a committee member at the July 1985 meeting.) Of course, the ability of lawyers to "do something" with the standard is probably equal to (or greater than) the standard's usefulness to its intended audience, grain elevator operators. Without guidance concerning the specifics of "proper maintenance," the lawyers will be as lost as anyone trying to glean any substance from the standard.
The extent to which 61B should contain such generalities appears to be the most significant issue facing the Agricultural Dusts committee. Some think that the committee has gone too far already. The president of one of the only two insurance companies presently underwriting grain elevators—major companies such as Cargill are self-insured—abhors the generality. He considers 61B so vague as to provide no real assistance in evaluating elevator safety. He does not even keep a current copy of the standard in his office. The technical director of the National Grain and Feed Association, on the other hand, considers such generalities the silver lining to an otherwise objectionable standard.
The generality problem indicates a more significant dilemma. The committee is trying to achieve two largely incompatible objectives: having a meaningful standard that can affect safety and provide helpful guidance to elevator operators without providing ammunition that will be used against you whenever an explosion occurs. Nowhere are the dimensions of this problem more accentuated than in respect to retroactivity.
By its own terms, 61B applies only to new facilities. This makes the most sense for design requirements. Compliance costs for many requirements are low in the design stage but very high after construction. Elevators used to be built with combustible materials, for example, and little consideration was given to minimizing ledges and horizontal surfaces or designing conveyors in a manner that would facilitate cleaning with portable vacuum cleaners. These things can easily be remedied in the design process. Correcting them retroactively would practically involve building a new facility.
In reality, 61B can, has, and will be applied to situations other than brand-new elevators. When issuing citations, OSHA often refers to 61B without regard for the date the facility was constructed. Plaintiff's attorneys are similarly inclined and have met with greater success. The retroactivity clause invites this attitude. NFPA 61B attempts to be unusually lenient in this regard. Unlike most building codes, it does not even require compliance in the case of major expansion or renovation—the vast majority of "new" construction. Moreover, the 1980 version also exempted from retroactive coverage a host of operational activities—such as hot-work procedures and housekeeping—that can be carried out without regard to the age or design of the facility.
The opposing viewpoints about retroactivity reflect deep-seated differences concerning the role and nature of private standards. Some of those favoring the broadest possible exemption from retroactive application "really do not want a standard at all," according to an Agricultural Dusts committee member at the July 1985 meeting. This group is not insignificant. The National Grain and Feed Association, the largest trade association in the field, is unwilling to refer to 61B as a national consensus standard and refuses to participate on any of NFPA's agricultural dust committees.
The implications of this reticence are not lost on the Agricultural Dusts committee. Organized opposition can prevent or at least postpone proposals from being adopted in the NFPA system. Should this private standard become unpalatable enough to the NFPA, or if others in the industry actively opposed it, 61B might fall of its own weight. As one committee member said at the July 1985 meeting, "It behooves us to try and give some relief to those being sued." Nevertheless, most committee members realize that the only real "protection" against retroactive application is to abolish the standard. They understand that others will do as they please in interpreting the retroactive effect of 61B, so it is futile to attempt to prevent this from happening by tinkering with the retroactivity clause. These members also see the danger in exempting too many requirements from retroactive effect. "If this [standard] is too unattractive to the states," warned another committee member at the same meeting, "they might adopt their own requirements." Several proposals to strengthen the tone of the retroactivity clause were rejected in July 1985 primarily because they seemed pointless to the committee.
To the chagrin of those proposing the stronger exemption, the committee adopted a proposal by the representative from Continental Grain
to narrow the scope of the retroactivity clause—that is, to make more provisions apply retroactively. The only provisions in the 1980 version with retroactive effect concerned fumigant usage. In seeking to identify appropriate candidates for retroactive application, the intent, according to the committee chairman, was to include "operational" requirements but not those requiring "even a dime of investment."
The results of the 1985 revisions are revealing because the committee chose to include the housekeeping provisions in the group to be given retroactive effect. This change appears to make 61B more credible. After all, shouldn't old and new facilities alike be expected to do proper maintenance or take precautions to ensure that welding is done safely? In light of the "not even a dime of investment" principle, however, the committee's action seems more significant for what it admits about the housekeeping provisions—that they do not require anything more than what an operator is already doing.
The Uneasy Solution: Change the Packaging
In an effort to placate those who would rather not have a standard, the Agricultural Dusts committee has done everything possible to make 61B a more agreeable document. These changes have largely been a matter of form, not substance. The language in 61B has been toned down considerably over time. References to such unpleasantnesses as "injuries to personnel" have been replaced with less specific references to hazards in general. The introduction to the 1959 version of 61B warned that: "GOOD HOUSEKEEPING AND CLEAN PREMISES ARE THE FIRST ESSENTIALS IN THE ELIMINATION OF DUST EXPLOSION HAZARDS, CONSEQUENTLY THIS CODE IS NOT INTENDED TO LESSEN IN ANY WAY THE RESPONSIBILITY OF THE OWNER AND OPERATOR IN THIS RESPECT ." This language was moved to the appendix in 1973, and the capital letters were replaced with regular capitalization. The statement was omitted entirely in the 1980 version. Only the gentlemen's agreement remains.
Placing things in the appendix is a popular compromise. Fully one-third of the 1980 version of 61B is appendix material. The appeal of this compromise is clear: the individual in favor of the material gets it "into the standard" in some form, while those opposed to the specifics take considerable solace in the fact that it is "not a requirement." Employee health and safety, a subject avoided in many NFPA standards but favored by the labor representative on the 61B committee, is addressed in an appendix added in 1980.
The appendix also contains more specifics than the actual standard. For example, the standard requires that "horizontal surfaces shall be minimized," while the appendix indicates that the "suggested angle of repose is 60 degrees." This is another tactic in the search for a liability-proof standard. The hope is that through the appendix the generalities in 61B can be given meaning in a nonenforceable manner. The official NFPA position, set forth in every standard, is that the appendix "is not part of the requirements … but is included for informational purposes only." Of course, one of the stated purposes of NFPA's "requirements" is to provide information.
The difference is really a matter of wishful thinking. All NFPA "requirements" are informational until an "authority having jurisdiction" chooses to enforce them. Moreover, the authority can choose to enforce the appendix as well as the "requirements" proper. An NFPA member who has worked with this committee confirms that appendix material is often treated by state fire marshals as having equal weight to the "requirements." The wishful thinking paid off, however, in the case of grain elevators. Some OSHA citations were overturned by the Occupational Safety and Health Review Commission precisely because they relied on material contained in the appendix of 61B.
Technical Arguments, Surprising Results
This is not to say that 61B is all appendix and no substance. Nor is it to say that disagreements are foreign to the Agricultural Dusts committee. Certain provisions in 61B are specific and have been the source of repeated debate throughout the years. Should there be a vent between bins to allow dust generated during loading to settle into adjoining bins instead of blowing back up into the work area? To what extent is it possible or desirable to vent silos and elevator legs to relieve pressure from an explosion? Should compressed air be allowed, and under what circumstances, to "blow down" dust from walls and rafters?
The technical nature of these questions is not surprising. Private standards-setting is often described as technical. Esoteric questions such as those above seem to fit the bill. How the committee has handled these issues is more unusual. "Irrational," "unrealistic," and "unduly stringent"—criticisms often reserved for government regulation—are all strictures used by some NFPA members to describe the resolution of these issues.
For example, even though most insurance and grain company rep-
resentatives privately concede that the requirement is irrational, 61B prohibits interbin venting, and it is also accused of being unrealistic about explosion venting. (Explosion vents are movable panels designed to vent the pressure from an actual explosion; interbin vents, just discussed, are actual openings designed to vent airborne dust.)
NFPA 61B includes several other provisions that are considered by many in the grain industry to be too stringent. Removing layered dust with compressed air is prohibited unless other equipment is shut off. The concern is that "blowing down" can create a combustible cloud. There are no known cases in which an explosion has occurred this way, and one insurance representative expressed serious doubts about whether compressed air could create dust concentrations above the LEL. The only explanation for this provision is that it represents a compromise between those who are opposed to blowing down on principle and those who think that it is never dangerous.
Requirements incorporating the National Electric Code's classifications for environments with agricultural dust are also quite strict. The code, written by NFPA, specifies two classes for such environments: Divisions 1 and 2. Equipment certified for Division 1 must be tested under conditions in which dust concentrations regularly exceed the LEL. Equipment for Division 2 is tested under conditions in which such concentrations are "occasionally" encountered. Herein lies the controversy. Division 2 equipment is tested under extreme conditions compared to those normally encountered in those parts of a grain elevator where Division 2 equipment is required. The Division 2 test methods do not just represent the worst case, they represent an impossible case. Not only does this provision increase the price of grain-handling equipment, but in some cases the required equipment is not available. The same arguments apply to Division 1 equipment if it is required in areas without explosive dust clouds. The NFPA leaves these implementation questions to "the authority having jurisdiction."
NFPA 61B is also stringent with respect to ignition sources in bucket elevators, but this is a recent development. Several requirements for bucket elevators were added in 1980, including (1) monitoring devices that cut off the power to the drive and sound an alarm when the leg belt slows down, (2) magnets or separator devices to minimize metal objects entering the grain stream, and (3) closing devices to prevent flame propagation through idle spouts. These requirements did not generate the controvery produced by those discussed above. Neither were they really new; they were moved from the appendix to the body
of the standard. This unusual move is best understood by the politics of the moment. The changes were suggested around the time OSHA initiated its Advance Notice of Proposed Rulemaking. Some committee members privately acknowledge that these changes were an attempt to forestall OSHA regulation. The changes certainly strengthened the standard, at least for new construction. But they did not forestall OSHA.