Is your safety knowledge on shaky ground?\nIt's time to check if
what you know is true or just a\nmyth.
by John F. Rekus, MS, CIH, CSP\n
Everybody knows that a 2-hour fire wall will\nhold up for 2 hours in a fire. Everybody knows that flammable liquid\ncans must have a flame arrester. Everybody knows that the atmosphere\nin a confined space can change in the blink of an eye. Everybody\nknows that respirator wearers can't have beards.
These and other myths have been repeated so\noften that many people think they're true. The truth is, what\neverybody knows is simply wrong!
I first became interested in safety myths about\n10 years ago after reading a report of a welder whose contact lenses\nfused to his cornea. Although this alleged incident was widely\npublicized, it was later shown to be a hoax. Nevertheless, the myth\nsurvives and I still get questions about it every now and then. This\nis just one of the many safety myths I've come across; here are a few\nmore.
Building Materials Fire Rating\n
Myth: A 2-hour fire door can withstand a\nfire for 2 hours. Fire rating has\nnothing to do with how long a door, wall, floor, or ceiling will\nsurvive in a fire. A case in point is a fire at a flammable liquids\nwarehouse in Dayton, Ohio, where 3-hour fire-rated walls crumbled\nafter only 23 minutes of fire exposure.
To understand fire rating, we must go back to\nthe 1930s when the National Bureau of Standards (now the National\nInstitute for Standards and Technology) did some research on flame\nspread rates in ordinary rooms. Engineers took a room with\n1930s-style furnishings and set it on fire. Thermocouples in the room\nrecorded the rate of temperature rise and the resulting data were\nreduced to yield what's become known as the "standard time\ntemperature curve."
The standard time temperature curve is still\nused to evaluate the acceptability of today's building materials.\nHere's how it's done. A manufacturer builds a prototype fire door and\nsubmits it to a testing laboratory such as Underwriter's Laboratory.\nThe test laboratory places the door on the open side of a huge\nindustrial oven and blocks up the annular space with refractory\nbrick.
The oven is then turned on, and the temperature\nis raised in accordance with the standard time temperature curve. The\nsurface temperature of the side of the door facing away from the oven\nis monitored by a matrix of thermocouples. The door's surface\ntemperature must remain below certain limits for a prescribed period\nof time. If the surface temperature exceeds the test criteria, the\ndoor fails the test. Fire tests for walls, floors and ceilings are\ncarried out in a similar way.
Now, consider this question. Are today's rooms\nfurnished the same as they were in the 1930s? Of course not! In the\n1930s, we used a lot of natural materials such as cotton and wood\nthat have low points of combustion. Today, most of our furnishings\nare synthetic. Even though the heat of combustion of these materials\nis much greater than ordinary combustibles, we still rely on the\n1930s data to establish fire ratings.
Flammable Liquid Safety Cans
Myth: Flammable liquid safety cans must be\nequipped with a flame arrester. One of\nthe interesting things about this myth is that OSHA is inconsistent\nwith respect to its requirements for safety cans. The construction\nindustry standard, 29 CFR 1926.155(l), requires a flame arrester; the\ngeneral industry standard, 29 CFR 1910.106 (a)(29), does not.\n
To shed some light on this inconsistency, we\ncan turn to the nation's leading authority on fire science, the\nNational Fire Protection Association (NFPA). In his book,\nFlammable Liquids Code\nHandbook, Mr. Robert Bennedetti, NFPA's\nresident flammable liquids expert, states, "The main purpose of a\nsafety can is preventing explosion of the overheated container [in a\nfire], while still providing the utility of a closed container. To\naccomplish this, a spring-operated cap is provided on the pouring\nspout, eliminating the need for a flame arrester in the spout. Even\nif the vapors coming past the spring-loaded cover are in the\nflammable range, their velocity would be at least an order of\nmagnitude greater than the intrinsic velocity of the flame through\nthe vapors, so flashback into the safety can would be unlikely should\nthe vapors be ignited from an external source."
Since the NFPA is an internationally recognized\nauthority in the field of fire science, and Bob Bennedetti is NFPA's\nflammable liquids guru, his opinion should be pretty persuasive. The\nbottom line -- simple physics keeps the flames from flashing\nback into the safety can, making flame arresters unnecessary.\n
Flammable Liquid Cabinets
Myth: Flammable liquid storage cabinets must\nbe ventilated. To understand this myth,\nyou have to understand the purpose of flammable liquid cabinets. \nSome people think they're supposed to contain a fire that might\nignite inside the cabinet, but that's another myth.
The cabinet's purpose is to protect its\ncontents in the event of a fire outside of the cabinet. This is\naccomplished by the cabinet's design, which incorporates double-wall\nconstruction with an insulating 1 1/2-inch air gap between the\ncabinet's walls.
The venting question is answered quite clearly\nin Appendix A-4.4.4 of NFPA-30 Flammable and Combustible Liquid Code,\nwhich states: "Venting of storage cabinets has not been demonstrated\nto be necessary for fire protection purposes. Additionally, venting a\ncabinet could compromise the ability of the cabinet to adequately\nprotect its contents from involvement in a fire since cabinets are\ngenerally not tested with such venting. Therefore, venting of storage\ncabinets is not recommended."
But if this is true, why do manufacturers equip\ncabinets with threaded knock-outs that facilitate attachment to\nventilation systems? As Appendix 4-3.3 indicates, some local\njurisdictions require venting. The appendix also cautions that if a\nventing system is installed, it should be done in a way that doesn't\nsubstantially affect the desired performance of the cabinet in a\nfire. This might be accomplished by installing thermally actuated\ndampers on the vent opening or by insulating the vent piping to\nprevent a rise in temperature inside the cabinet.
Myth: Compressed air for air-supplied\nrespirators should conform to Compressed Gas Association Commodity\nSpecification G7.1(1966) as required by OSHA standard 29 CFR\n1910.134(d)(1). If you follow this OSHA\nstandard, the NIOSH certification on your respirator will be void. \nHere's why. The 1966 edition of G7.1 allows breathing air to contain\nup to 20 ppm of carbon monoxide. The latest edition, on the other\nhand, sets a limit of only 10 ppm. Since NIOSH requires conformance\nwith the latest edition of G 7.1, following the OSHA standard voids\nthe NIOSH approval.
Myth: OSHA standards require that all\ncompressed gas cylinders be secured from falling. It's certainly a good practice to secure compressed\ngas cylinders from falling. In fact, some model building codes such\nas the BOCA National Building Code require it. But OSHA standards\nonly require that cylinders used for oxy-fuel gas welding and cutting\nbe secured. How can this be?
Well, OSHA's compressed gas standard, 29 CFR\n1910.101, incorporates by reference Compressed Gas Association\nPamphlet P-1 (1965). Curiously, P-1 (1965) does not stipulate that\ncompressed gas cylinders be secured. Since P-1 does not require\ncylinders to be secured, failure to do so cannot be a violation of 29\nCFR 1910.101.
Myth: Respirator wearers can't have beards.\nThis myth is based on OSHA standard 29 CFR\n1910.134(e)(5)(i), which states:\n"Respirators shall not be worn when conditions prevent a good face\nseal. Such conditions may be a growth of beard...."
The issue of beards and respirators has been\naddressed a number of times by OSHA in letters of interpretation. \nOSHA has repeatedly pointed out in these letters that it is not the wearing of beards that is the issue, it's\nthe face-to-face- piece seal. In other\nwords, Santa Claus could wear an air-supplied hood or helmet whose\nfit would not be affected by his beard. Colonel Sanders might even be\nable to wear a tight-fitting respirator provided his goatee did not\ninterfere with the face-to-facepiece seal.
Myth: It's a serious violation of OSHA\nstandards for respirator users to wear contact lenses. This myth is based on OSHA standard 29 CFR\n1910.134(e)(5)(ii), which states: "Wearing of contact lenses in\ncontaminated atmospheres with a respirator shall not be allowed." \nYet, research conducted by Lawrence Livermore labs showed that\nfirefighters who wore contact lens had fewer problems than those who\nwore "approved" eyeglass inserts inside of their respirator\nfacepieces.
In debunking this myth, we find that the OSHA\nstandard is based on a 1968 ANSI standard. Back in 1968, only hard\ncontact lenses were available. Since these lenses had a tendency to\npop out, they were prohibited. With today's soft contact lenses, this\nis no longer a problem. This issue, like beards, is addressed in an\nOSHA letter of interpretation that explains that wearing of soft\ncontact lenses with a respirator is a de minimis violation. In other\nwords, it's insignificant and doesn't carry a fine.
Myth: Powered air-purifying respirators\n(PAPRs) can be used in atmospheres up to 1,000 times the OSHA\npermissible exposure limit. There is a\ngrain of truth to this myth. Both the coke oven emission standard and\nthe general industry lead standard state that PAPRs have a protection\nfactor of 1,000. But here's the interesting part. In the 1980s, NIOSH\nconducted some field studies to determine how effective PAPRs were\nunder actual workplace conditions.
What NIOSH found was alarming! In one study\ninvolving tight-fitting half-face PAPRs, researchers found the\naverage protection factor to be only 376. In another study of\nloose-fitting helmets, they found an average protection factor of\n182. Although NIOSH warned the public about this problem in users'\nnotices published in 1982 and 1983, many people are unaware of these\nnotices and continue to rely on the OSHA standards.
Myth: Organic vapor respirator cartridges\nprovide protection from organic vapors.\nOrganic vapor cartridges protect against some, but not all, organic\nvapors. Since odor breakthrough is used to determine when organic\nvapor cartridges should be changed, they can only be worn to protect\nagainst substances whose odor threshold is less than the PEL.\n
However, some organic vapors such as allyl\nalcohol and carbon tetrachloride have odor thresholds greater than\nthe PEL. That means that by the time you smell them, you're already\nover the standard. If you don't know the odor threshold, you better\nnot be using organic vapor cartridges. If you want odor threshold\ninformation, contact the American Industrial Hygiene Association at\n(703)849-8888 and order a copy of Odor\nThreshold for Chemicals with Established Health\nStandards.
Myth: Faceshields may be use as eye\nprotection. Like many other myths, this\none contains a grain of truth. According to ANSI Z88.9, faceshields\nare secondary protection that must be worn in conjunction with\nprimary protectors such as safety glasses or goggles.
Myth: Commercially available squeeze\nbottle-type eye washes meet the requirement of OSHA standard 29 CFR\n1910.151(c), which requires "suitable facilities for the flushing of\nthe eyes and body injurious corrosive chemicals." ANSI Z-358.1-1990 explains that squeeze bottle-type eye\nwashes, actually called personal eyewashes, are "...a supplementary\neyewash that supports plumbed units, self-contained units or both..."\n Thus, a personal eye wash alone is insufficient.
Myth: Material safety data sheets are a\nuseful source of information for chemical hazards. Although some material safety data sheets provide good\nhazard infor-mation, the quality of MSDSs varies widely. Some are\nclear, concise and contain user-friendly information. Others are so\ncomplex that you need a Ph.D. in toxicology or organic chemistry to\nunderstand them. And still others aren't worth the paper they are\nprinted on! While MSDS quality has improved over the last decade,\nmore improvement in preparation is required before they can be\nuniversally considered a good source of hazard information.\n
Consider, for example, the data sheet that a\nparticipant in one of my indus-trial hygiene courses brought in to\nclass. It was an MSDS for distilled water from a nationally known\ndistributor of reagent grade chemicals. The data sheet indicated that\n"appropriate eye, skin and respiratory protection should be worn"\nwhen handling water. Containers of water were supposed to be kept\n"tightly closed." If you got water on your skin or eyes, you guessed\nit, you were supposed to "wash with [water] the exposed area for at\nleast 15 minutes." I wondered who it was that could write such\nsilliness.
While working for a regulatory agency, I once\nreviewed a data sheet for crystalline silica. Among other things, it\ncontained a warning to "wear a mask." I thought that the Lone Ranger\nand Batman might be well prepared, but what about the rest of us?\nWhat kind of mask were we supposed to wear? I called the data sheet\nsupplier and spoke to the data sheet's author. He was absolutely\nclueless as to what was required. "You know," he said, "wear one of\nthem industrial dust masks." Obviously, he knew nothing of NIOSH\napprovals, protection factors and other critical items that would\nallow selection of the appropriate respirator.
But is this really any worse than all those\ndata sheets that tell us to "wear only OSHA-approved respirators,"\nwhen OSHA does not in fact approve any personal protective equipment,\nincluding respirators? Or to "use only explosion-proof equipment"\nwhen intrinsically safe or purged-and-pressurized equipment is\nequally acceptable according to the National Electrical Code?\n
Myth: The atmosphere in a confined space can\nchange in the blink of an eye. I was\nguilty of repeating this myth until I wrote my book, The Complete Confined Spaces Handbook. As I was writing the chapter on instruments, it\noccurred to me that the laws of chemistry and physics prohibit the\natmosphere from changing instantaneously. For example, the oxygen\ncontent in a space won't be 20.8 percent one minute and 0 percent the\nnext.
Yes, the atmosphere in a confined space can\nchange, but it always changes at some rate. If the space is monitored\ncontinuously with a properly calibrated instrument set to alarm at a\nspecified set point, the alarm will sound, signaling entrants to\nevacuate.
Although it's unlikely that confined space\natmospheres will change instantaneously, they can change day-to-day\nor week-to-week. This is the reason why past history of a space's\natmosphere doesn't provide any indication of its present condition.\nConsequently, it's prudent to not only test confined spaces prior to\nentry but to also provide continuous monitoring when workers are\ninside.
Myth: Confined space instruments should be\nused in accordance with the manufacturers'\nrecommendations. While this sounds\nreasonable, some manufacturers' instruction manuals recommend their\ninstruments be calibrated every 30 days. By quizzing a product\nengineer who was exhibiting his wares at a professional conference, I\ndetermined that the 30-day recommendation for his instrument was\nbased on its stability on a lab bench.
Most people, though, don't leave their\ninstruments on a bench. They have them thumping around in the back of\na pickup truck. A lot of things can happen when you jostle an\ninstrument around. A lead can break, a sensor can work lose, a trim\npot can drift, a circuit board can crack. Without checking the\ninstrument prior to each use, there is no way to assure that it is\nresponding properly.
Myth: A confined space rescue team must be\nlocated no more than 4 minutes away.\nThis myth first improperly assumes that there must be a confined\nspace rescue team. Careful reading of the OSHA standard shows that\nthis is not the case at all. The standard stipulates a number of\nthings that must be done if there is a rescue team, but it does not\nrequire that there be a rescue team. What is required is a rescue\nplan.
Nevertheless, the 4-minute rescue team myth is\nbased largely on the assumption that the atmosphere in a space will\nbecome oxygen-deficient. In that case, failure to quickly revive the\nvictim may result in death or permanent brain damage. But this\ncatastrophic situation is not the only type of emergency that might\narise. As I discussed in my November 1995 article, "Confined Space\nRescue Planning," there are other, less life-threatening emergencies\nthat permit less timely responses without increasing the\nrisks.
Furthermore, in some cases, you may not even\nneed a special rescue team. For example, the attendant outside the\nspace may be able to use a rescue winch to hoist a victim out of a\nspace.
But even more important, if you have to rescue\nsomeone from a confined space because of an atmospheric hazard,\nyou've screwed up REALLY BIG TIME. Why weren't you monitoring the\natmosphere continuously as discussed above?
Myth: Local fire departments can be used as\nconfined space rescue teams.\n
It's unlikely that local fire departments will\nbe able to provide confined space rescue services. Here's why:\n
First, members of the fire department rescue\nteam must be trained as confined space entrants. Most firefighters do\nnot have this training.
Second, the team must be equipped for confined\nspace rescue. Since SCBA air cylinders will not fit through many\nmanholes, and removal of bottles and passing them through the manhole\nvoids the SCBA's approval, rescuers must have pressure-demand\nair-line respirators with adequately sized escape bottles. Many fire\ndepartments lack this equipment.
Third, the OSHA standard stipulates that\nresponders be afforded an opportunity to visit the site to preplan a\nrescue. This is seldom done.
Fourth, members of the rescue team have to\npractice their skills at least once a year by retrieving equivalent\nloads though portals similar to the one they encounter in the\nemergency.
Even if a department has a rescue team that\nmeets these criteria, firefighters trained to respond to confined\nspace emergencies might be on other calls.
Anybody Can Be a Safety Director\n
Myth: Safety is just common\nsense. Sense is not common, and common\nsense would tell you that the world is flat. Safety problems are not\nsolved by common sense; they are solved by the application of\nsophisticated knowledge. Many safety concerns embody complex\ntechnical issues that demand complex technical solutions!
For example, common sense won't tell you how\nmany sprinkler heads you need in a flammable liquid warehouse. Common\nsense won't tell you the air velocity needed to capture welding\nfumes. Common sense won't tell you what type of gloves to use when\nworking with dimethyl-bad-stuff. No, clearly the solutions to each of\nthese problems demand expert technical knowledge, not common\nsense.
Myth: Anybody can be a safety\ndirector. Because so many people\nbelieve incorrectly that safety is just common sense, my observations\nsuggest that many unqualified people are named into positions of\nsafety responsibility. They might have done a great job managing the\nhuman resources department, or the loading dock or even\nmanufacturing, but they don't know a mask from a respirator or NIOSH\nfrom Oshkosh. Many are totally lacking in the requisite skills\nnecessary to manage complex issues.
CEOs, take note. You wouldn't let a billing\nclerk rather than your CPA file your corporate tax returns. Why would\nyou allow someone other than a CSP or CIH to manage your safety\nprogram?
As Nazi propaganda minister Joseph Goebbels\nonce said, "If you tell a lie often enough, people will eventually\nbelieve it." This seems to be the case with safety myths. Many\nuntruths, myths and legends are repeated so often that people believe\nthem. Even worse, they pass them on to others.
I encourage participants in all of my training\ncourses to be suspicious, to question authority, to ask why, and when\npossible, to do their own independent research, because what\neverybody knows to be true is often wrong.
BIO: John Rekus is an independent consultant\nand author of the National Safety Council's Complete Confined Spaces\nHandbook. With more than 20 years of regulatory experience, he\nconducts OSHA compliance audits and provides training seminars for\nworkers, managers, corporations and trade associations. He lives in\nBaltimore and may be reached at (410) 583-7954.
Occupational Hazards, October 1996, page 139