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MALCOLM M. RENFREW University 01 ldaho MOSCOW, ldaho 83843
Control of Hazards in Laboratories Robert B. Scott. Jr. University of Mississippi, University, Mississippi 38677
The control of hazards in laboratories involves all aspects of their operation, from attitudes and regulations, to facilities in and attendant to the laboratory, to inspections and the handling of accidents. These have been grouped in outline form in eleven categories for this presentation. A. B. C. D.
Safety Attitudes Safety Regulations Laboratory Facilities Safety Features Vicinal to the Laboratory E. Central Storage of Chemicals for Laboratories F. Disposal of Chemical Waste from Laboratories G. Ventilation System H. Inspections I. Accidents in the Laboratory J. Near Accidents in the Laboratory K. Injuries in the Laboratory The decree of control of hazards is inv~melypruportionnl 10 the degree of nmern. Evrryone from tup managrment, t u terhniriansand rtudenrp, ro maintrnanceandpnitorial staffs, and even to visitors, must have a proper attitude toward safety, out of the laboratory as well as in it, if we are to maintain control of hazards in laboratories effeetively. Thir requires drliberate thotrghr, effort, and cmp~rntionon the pan of everyone involved in the oprration of the lahnraruries. ~
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Safety Attitudes I. Necessary degree of control inversely proportional to safety attitudes 11. Those directly involved a. Management b. Laboratory designers c. Experimentalists d. Technicians e. Trainees (students) f. Supply and purchasing personnel g. Janitorial staff h. Maintenance personnel i. Medical personnel j. Security forces k. Visitors
Hazards in laboratories can be controlled, just as traffic hazards can be. But just as traffic hazards are greater in one ease than in an apparently similar one, some laboratories may be far more hazardous than similar ones. With both traffic and laboratories, this difference is a reflection of overall safety attitudes. A. 111. Must he enthusiastic attitude IV. Must be common sense attitude V. Must reflect deliberate thought and cooperation of everyone involved Since experienced forethought is necessary for safety in the laboratory, carefully thought-out safety regulations are needed to help ensure that all involved are prepared. The American Chemical Society manual on "Safety in Academic Chemistry Laboratories" is a good basis, however, appropriate modifications and supplementary regulations and discussions will be needed for various personnel and situations. B.
Safety Regulations. I. General published materials including: a "Safety in Academic Chemistry Laboratories", American Chemical Society, 1976. b. Quam, G. N., "Safety Practice for Chemical Laboratories", Villanova Press, 1963. c. "Safety in the Chemical Laboratary", collected volumes from Journal of Chemical Education. d. "Safety Handbook" included in catalogs of Matheson, Coleman, Bell. e. Meyer, E., "Chemistry of Hazardous Materials", PrenticeHall, New York, 1977. f. "Manual of Hazardous Chemical Reactions 1971", National Fire Protection Association. g. "Laboratory Waste Disposal Manual", Manufacturing Chemists Association, 1970. 11. Individualized guides along lines oE
a. Four-Part series for Smith, Kline, and French Laboratories: 1. "A Guide to Laboratory Safety" 2. "Working Safely in a Laboratory" 3. "Supervising a Safe Laboratory" 4. "Chemical Safety Supplement" b. Other industrial laboratory safe* midelins as in Collected Val. 2 i f " ~ s f e t v i nthe Chemical ~aboratory', N. V. Steere, ed., J. Chem. Educ. 1) Merek, Sharp and Dohme Research Laboratories. 2) Honeywell Corporate Research Center. 3) Mallinckrodt Chemical Works. 4) Monsanto Chemical Campany Research Center. 5) Lederle Laboratory Division, American Cyanamid Company. c. Academic safety guidelines as in Collected Vol. 2 of "Safety in the Chemical Laboratory". 1) Ohio State University. 2) Harvard University. ~
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There should be frequent reinforcement of proper safety practices.
111. Periodic lectures on safety a. Always include calls for suggestions Remedial actionsh~uldbe taken whenev. er disregard fm snfery becomes known. Miaunderstandings may require clarifying modifications in the regulations.
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N. Infractions of safetv .reeulations a. Repeated violation by various individuals 1. Reviewed by peers and management (a) Rectify communication breakdown (b) Modify regulations as appropriate (c) Safety meeting of all personnel (d) Warning issued Some disciplinary action should he taken for repeated or flagrant infractions, while accident-prone personnel ought to be assigned work in a less hazardous situation. h. Repeated violation by individual 1. Reviewed by peers and management (a) Rectify communications breakdown Ib) Warning issued (c) Penalty assessed (dl Dismissal of individual c. Flagrant violation 1. Reviewed by peers and management
(Continued on page A131) Volume 55, Number 3. March 1978 1 A129
Safety
fumes, the long-term effeem of which are not fully known. This could he the case in any Lahrstory in which the workern are relatively close together.
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(a) Warning issued (b) Penalty assessed (c) Dismissal of individual Every laboratory should have a t least two readily accessible exits whieh open outward. Any special emergency instructions for fire and rescue should be posted outside.
C.
Laboratory Facilities I. Exits a. At least two exits located to avoid entrapment 1) Knock-out panel as minimum second exit h. Adequate precautions against blocking exits c. Doors should open outward or both ways d. Doors should have view panels e. Doors should provide for posting of warnings 1) Warnings for the visitor 2) Warnings regarding procedures for potential emergencies f. Openable windows 1) For escape and ventilation breakdown
Laboratory benches should be arranged for unhindered alternative passage to exits.
Il. Work benches a. Placement 1) Longitudinal to door for freer exit 2) Open ended (a) For alternate psasage to exit (b) For access to knockout panel (c) For securing gas cylinders b. Aisle space 1) 5-Fwt minimum between benches to allow stepping back suddenly Hose type eye wanhers should be located at each bench bur away from thesink toavoid waste contamination.
Adequate ventilation 1) Small individual hoods to diminish routine l d i z e d vapors
Grounding electrical outlets is not enough protection in a laboratory where the floor might be wet or where there is much electrical equipment. Ground-fault circuit breakers should be mandatory in laboratory buildings. f. Grounded electrical outlets backed up by ground-fault breakers 1) Located to minimize cluttering work surface 2) Located to avoid contaminants 3) Sufficient outlets to avoid extension outlets Raised edges on bench tops can help contain a fire by confining spills, and thorough clean-up of hazardous liquid spills from the floor is more nearly possible if benches rest on pedestals. Other design features of the work bench can help control hazards in the laboratory. Edge guards on reagent shelves Marine edges on bench to confine spills Pedestal support for bench 1) To facilitate cleaning floor of spills 2) To provide toe room Drawers 1) Stops to avoid unintentional removal 2) Long drawer at bottom to avoid tripping hazard Control valves readily accessible 1. Preferably below front edge of bench to avoid reaching across apparati Considerate thought sbould be given to location and orientation of all service Lies at the laboratory bench. There sbould be enough so located to avoid unnecessary clutter. Valves should be at bench front.
2) Sealed to alert inspectors it has been used
1. Steam, low pressure 1) Insulated lines 2) Recessed or insulated cones 3) Outlets directed downward 4) Shut-off valve for line at bench m. Compressed air 1) Regulated to 5 psi maximum 2) Outlets directed downward 3) Shut-off valve for line at bench n. Burner gas line 1) Located to minimize clutter
In planning a training laboratory it should be recognized that trainees can create
(Continued on page A132)
c. Eye wash at bench 1) Flexible hose type, not Located at sink, aerated Small fire eatinwishers near at hand are indispenaihle for putting our a fire before it gets out of control. d. Primary fue extinguishers at
. dry chemical as appronrinte r - ~ -
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. .. 2) Sufficient outlets 3) Shut-off valve for line a t bench o. Water line 1) Located to minimize clutter 2) Outlets directed downward 3) Sufficient outlets 4) Shut-off valve for line at bench p. Vacuum line 1) Located to minimize clutter
Good planning of the wash-sink area and appropriate waste disposal is essential. q. Wash sink 1) Readily accessible to minimize dirty dish transport 2) Hot water mixer 3) Hand soap and towels 4) Drain rack aver sink 5 ) Receptacle for cleansers and brushes 6) Cleaning solvents in cabinet under sink 7) Sink plug removable above water Level 8) Drainage segregated from sanitary drainage
9) Waste disposal cans at sink (a) For nonchemical waste (b) For chemical solid waste (c) For chemical liquid waste (1) Safety can for disposal of hazardous solvents and flammable liquids (d) For special waste (may be better located) (e) For broken glass
Necessary wlatilc solvents and corrosive mawrialoshould he stored in low, ventilated cabinets r. Storage of volatile solvents when necessary for the work bench 1) In safety cans in forced ventilated cabinets venting to exhaust duets s. Storage of corrosives when necessary for the work bench 1) In ventilated cabinet provided with corrosion resistant catch pan 2) Segregated storage for incompatibles
Location of pressurized gas cylinders should be plannedto avoid heavy traffic area8
and prevention of a cylinder being knocked over.
t. Permanently mounted restraints for securing gas cylinders i n s safe location u. Permanent % in. racks a t back of benches for securing apparatus Safety showers are near the top of the list of essential facilities for dealing with an emergency. They should be readily accessible and used to wash away chemicals spilled an clothing and to extinguish blazing clothing. A quick-opening valve requiring manual closing should be operated by a downward oull delta bar or wall-mounted dual-direction iong-llandl~rlvalve. Chain pulls are hazardOUR and ought to he illegal. I t must Le impossible to shut off water to the shower line without turning off all water.
111. Safety Showers a. Located at wall where readily accessible 1) Avoid potential fire barrier 2) Avoid electrical facilities (switches, light, circuit boxes) b. Quick opening valve 1) Must reauire manual closing 2) Valve handle rigidly fixed and plainly labeled for operation (a) Downward pull delta bar satisfactory if long enough fb) . . Wall mounted valve should open in either direction (c) Foot or knee operation subject to aecidental opening (d) Avoid chain pull (1) Clumsy to grasp in emergency (2) Tall person will hang it out of reachof shorter people to prevent hitting his head (3) Breakage of chain likelv . uDon . corrosion 3) Strong eorrosion-free mechanism e. Must not have shut-off valve 1) To repair must require turning.off . general water system (a) Otherwise negligent shut-off of shower might escape notice d. 3-Ft or greater radius for shower to accommodate more than one person 1) Copius volume sufficient to drench subiect immediately e. Shower and shower area set off by painting the shower assembly wall and floor fluorescent red and by an operational sign (Continued on page A1341
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Safety
.. . 1) Painted area kept clear at all times
A fire blanket, which is to he usedprimarily for protection from shock prevention rather than smothering burning clothing because it does not remove beat, should be located near the safety shower. (Nor should a fire extinguisher he used on aperson, since it could suffocate him.) IV. Fire Blanket near safety shower a. Used for protection from shock. Shower is used for fire A first aid station should he designated soley for that purpose and not for the medical treatment which only a professional should render. An air pack may be essential, and a resucitation device advisable, for rescue. An amyl nitrite vaporole may he needed after resocitation. A direct comoress.. not a tournaluet, i i advised for suppreraion of bleeding. An npprwed emetic may I w or value. M'lth the p ~ b i i t hexceptim uf a proterrrd, dean eye cup, no other first-aid equipment is advised. No unguents, no aspirin, no bandages should he kept. ~~
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First Aid a. Self-contained
air
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readily available for rescue h. Resueitation devise c. Amyl nitrite vaporoles d. Compress pads to supress bleeding e. Approved emetics for ingested poison f. Eye cup for washing eye, kept clean in plastic wrapper Equipment routinely used for safety protection, rather than emergencies, should be stored in a convenient. well-identified location in the laboratory. Such should be periodically inspected. VI. Storage of protective safety devices conveniently located a. (;ogglei and face shields b. Free standina shields 1) Air cushion between inner ~olvcarbonate and . outer safety glass panes, 70" *lope, heavy base. low renter ol gravity. Quam design 2) Parabolic curved polycarbonate, heavy base, low center of gravity 3) Combination design with air cushion feature of 1. and parabolic feature of 2. highly desirable c. Various approved gloves
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At each exit there should be a control for sounding an evacuation alarm for the lahoratory. This should be set off automatically
when a fire alarm is activated. Heat sensors in the laboratory should sound the fire alarm. In most laboratories smoke (photoelectric) or ionization alarms as fire detectors would be unsatisfactory because of fumes. Sprinkler systems would be of dubious value in most laboratories.
VII. Fire detectors and alarms a. Evacuation alarm, control at each exit 1) Set off by fire alarm automatically b. Heat sensors but generally no smoke or ionization detectors advisable 1) Generally not with a sprinkler system Hoods should not be in heaj. traffic areas. Exhaust fans should he above the roof and draw supplemental tempered air through the hood. A total air flow of 150linear ft/min is recommended a t the hood face. Horizontal andvertical air flow should be balanced and drafts from traffic should he foiled. Special hoods, e.g., perchloric acid and radioactivity hoods, should be so designated with signs. VIII. Fume hoods, backed up with emergency power source. a. Located out of traffic area h. Exhaust fanon roof, venting at least 16 ft above roof c. Supplemental air not recommended (Continued on page A140)
Safety
.. . 1) If used for energy conservation, install automatic shut off upon decrease in exhaust fan efficiency 2) If used, temper to avoid dew condensation d. Air flow 150 linear ftlmin a t fully open hood. e. Hood window of safety glass f. Adjustable baffle designed ta balance horizontal air flow across entire surface of hood with that of vertical flow, with minimum turbulence while operator at work 1) Continuous balanced flow with closed hood g. Draft foils to minimize effect of outside turbulence from traffic h. Valve controls outside i. Electrid outlets inside hwd and grounded j. Explosion and corrosion proof light k. Pedestal support to facilitate cleaning of spills 1. Sign forbidding perchloric acid or radioactive materials m. Perchlorie and related hoods
of stainless steel, including duets. 1) Sien forbiddine ,. owanicor .. radioactive materials n. Radioactivity hood uf xtainless steel aith stainless steel ducts and approved exhaust air filter 1) Sign prohibiting other use The ideal floor has yet to be found and more research is needed. I t would be smooth, impervious, seamless, and seratch-free to facilitate cleaning, be skid-proof, static-free, and yet comfortable. Any floor drains should have water maintained in trap automatidy, possibly by continuous small flow. Because of potential leaks around the drain, it may be advisable to forego drains except on the ground floor. To prevent seepage to a lower floor, service lines should go through raised islands.
IX. Floor a. Smooth, seamless, impenrious surface 1) Removable panels hazardous 2) Seams trap minute globules of mercury b. Minimum surface covered by permanent fixtures to facilitate cleanup of spills c. Floor drains generally of dubious value. Mopping up may be better.
1) Automatic water level
device needed if any drains d. Raised island for service lines at floor entrance to prevent seepage to lower floor The laboratory should be kept free of all but essential furniture, which must not interfere with free exit. X. Furniture a. Desk and chair only when necessary 1. Situated near exit (a) Avoid possible interference with traffic b. Stools only where necessary 1. Backless (a) Back hampers facile movement 2. Metal (a) Wwdor plastic absorbs organics c. File cabinet only when necessary 1. Located not to interfere with traffic 2. Designed not to overturn when all loaded drawers are open 3. Sufficiently movable for spill cleanup d. Bookcase, wall mounted or on desk only Electrical and mechanical equipment should be thoughtfully equipped for safe operations. XI. Equipment a. Electrical 1) All grounded and fused 2) Only approved watermaof wirine 3) Explosion-proof motors ra) Avoid brush motors 4) Thermostats external mercoid type 5) Heater coils confined (a) Imbedded in eerami a , or in mineral wwl or glass wool, or sealed 6) Variable transformers in place of variable resistors b. Mechanical 1) Belt drives shielded 2) Shear pin or slipcluteh if driven by 114 hp or greater Especially in training laboratories, appropriate precautionary signs should be prominently displayed. XII. Signs in laboratories, especially academic laboratories a. Operation of safety shower b. Extinguishing fires c. List of common highly flammable solvents, class 4 1) Precaution to extinguish all flames 2) Precaution to turn off motors
(Continued on page A144) A140 / Journal of Chemical Education
Safety
... d. List of common flammable solvents, class 3 1) Precautions to avoid nearby ilame or operating motor e. Emergency telephone numhers f. First aid instructions 1) Cardio-pulmonary resucitation 2) Bleeding 3) Burns 4) Shock g. Precautions regarding clothing, hair, and glasses 1) Natural fibers satisfactory in general for clothing (a) Synthetics which melt or burn unsatisfaetory in general 2) Avoid wearing loose sleeves, ties, etc. 3) Shoes should have low heels and not he open (a) High heels, open shoes, sandals prohibited (b) Bare feet nonpermissible 4) Long hair restrained, including beards (a) Trim or use an appropriate hand or net
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5 ) Approved
glasses required (a) If contact lenses necessary, goggles required
Clutter in the laboratory should be minimized by appropriate storage of chemicals and equipment except for general reagents and mounted eauinment. Storaee of chemieals should be systematic hut wi& due regard to hazards. Records should be kept up to date. XIII.
Storage in laboratory a. Except for general reagents, permanently mounted equipment, and items in freauent use. chemicals and eqwpment should be stored 1 1 Vcdatile and corroslvc suhstances for general laboratory use (a) In ventilated cabinets (1) Farced ventilation connected to exhaust ducts for volatiles (2) Valatiles in safety cans (3) Corrosives in corrosion resistant catch pans (4) Incompatibles segregated 2) Other chemicals, in eabinets
(a) Incompatibles segregated (b) Inorganics and organics segregated (c) Arranged systematically (1) Grouped by type and arranged by common names, sometimes requiring additional label (2) Same but arranged by label names, sometimes requiring additional label because of dlfference in supplier's naming policy (d) Record of aequisition (1) Card file arranged as in (e),cross referenced according to alternative in (c) (2) Card for lahoratory file made out while withdrawing from stock. Should show acquisition date, supplier, quality, amount, etc. Card should be updated upon replenishment or removed from file upon exhausting material. (To he concluded in the April issue.)
