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in the Chemical f aboratory Edited by N O R M A N V. STEERE, 140 Melbourne Ave., S.E. Minneapolis, Minn. 5541 4
LXXXIX. Fire Safety Standard for Hospital Laboratories N O R M A N V. STEERE The National Fire Protection hsociation, GO Brttterymarch Street, Boston, Mass. 02110, in 1970 adopted a revised Safety Standard for Hospital Lshoratol.ies ahich could be a usriul guide in any laboratory where chemicals are handled. This article will describe the Standard briefly and focus on four particular requirement*: fire resistant construction, automatic extinguishing systems, flammable liquid limits and storage, and hazard identification. These four suhjeets deserve partieular attention and critical evalurttion hecause they may become part of later NFPA standards which are being adopted by reference as regulations under the new Occupational Safety and Health Act governing all TJnited States employers engaged in commerce. The Standard defines a. hospital laboratory as being located in part of a building providing inpatient care and involving procedures for investigation, diagnosis or treatment in which flammable, cambu.tible, or otherwise hasardous meterials are to be used. Clinical ~ervice a r e a not using hazardous materials are excluded from the definition, as are lahhoratories in separate buildings and in health care facilities withno inpatient care. The NFPA Safety St,andard for Hospital Laboratories conisis of six sections: Introduction and Scope; Nature of Hasardq; Structure, Equipment and Fire Protection; Flammable and Combmtible Liquids; Gases; and Msintenmce and Inspection. In the first section the fire hazard problem is stated, the need to protect the facilities and personnel for patient care is emphasized, and definition of terms are presented. The terms defined include flammable liqrdds, flash points, safety cans, laboratory-safe refrigerators and other terms relating to fire hazards.
Nature of Hazards The section on Nature of Hazards stresses the need for knowledgable, attentive handline of flammable. combustible. employees, on .mfe practices, continuing education and supervision, and on regular inspection and fire training.
Structure, Equipment, a n d Fire Protection A major portion of the Safety Standard for Hospital Laboratories is in the section a n Struet,ure, Equipment and Fire Pro-
tection. The section is subdivided into requirements on construction and arrangement, exit details, equipment, fire protection, and emergency water supplies.
Consiruction and Arrangement The Standard requires t,hat hospital laboratories he separated from other hospital areas and from exit corridors by construction with s. fire-resistance rating of 1 hr minimum. Laboratory w a l k of tile, block, or plaster a1.e usually constructed with a minimum of 1 hr fire resistance. However, if a laboratory or adjoining corridor has s suspended ceiling with layin pen& that are not securely fastened in place there is no fire resistant separation unless the wall runs up tightly to the bottom of the floor above. Although the Standard does not specify limitations an doors and windows in corridor walls of 1-hr fire resistilnce rating, the 1970 NFPA Life Safety Code does give specifications which might be used far laboratories. The Life Safety Code does not require 1-hr rated doors, but does set a minimum of ls//Fin solid core wood doors without undercuts or louvers, with latches, and a maximum vision panel in the door of 720 sq in. of wired glass installed in approved steel frames. The Life Safety Code allows fixed vision panels of wired glass in corridor walls if the panels are installed in steel frames and do not exceed 1,296 sq in. in size. The Standard specifies a maximum flamespread rating of 25 on interior finish in laharstories and corridors to exits. The limit of 25 is on a scale with 0 for cement asbestos board and 100 for red oak board. This requirement would necessitate replacement of combustible fiber acoustical 'ceiling tile and plywood .*all surfacings, or that such finish be effectively coated with flame retardant coatings with a. Class A flrtmespread rsting listed by Underwriters Laboratories, Inc.
Exit Detoils
To safeguard personnel and patients, two exits are required for any laboratory in excess of 1,000 sq ft. Exit doors not intended for patient care are to be a t least 36 in. wide, and if tho door is to he used for in-patients it is to be 46 in. wide. Doors for access or exit from s, laboratory must he of a type that swings rather than slides or folds. Laboratory corridors not used by patients should be s t least 5 f t wide, and if used by patients they should be S f t wide.
feature
Fire Profedion The NFPA Safety Standard for Hospital Laboratories establishes as a requirement "Laboratories, inchding associated storage rooms, enclosures, and the interior of fume hoods shall he protected by a fixed automatic extinguishing system." The Standard also requires that fire extinguishers shall he provided for the particular hazards present. The most economical and effective single extinguishing agent for hospital laboratory fires is water, whioh will extinguish paper and packaging fires and cool exposed enntainen. Water applied through spray noaales on fire hoses can cool and extinguish many flammable liquid fires, and water will probably be the only extinguishing agent used by the Fire Department on laboratory fires unless they bring a. carbon dioxide or dry chemical extinguisher. Dry chemical ((usually sodium bicarbonate treated to flow) is the most effective extinguishing agent for use on flammable liquid fires that may be larger than s. few sq ft. Carbon dioxide extinguishers of a convenient size, 5 lb capacity, are best for small bench fires hut have s. reach of only a few feet and are offeotive only on a small fire a few sq f t in ares. Larger carbon dioxide extinguishers are not generally reconmended for laboratory use because of their weight, limited reach, and limited extinguishing capacity. Dry chemical extinguishers have a greater reach and extinguishing capacity per pound and are most effective on large spill fires such as mny be expected from gallon glass hott,les. Although the only drawback t,o the use of dry chemical extinguishers is the insulating en'ect on electrical eantncls, which would require careful cleaning, the more severe damaging effects of h1.e un electrical equipment would warrant use of dry chemical on fires beyond the capability of carbon dioxide extinguishers. Fires in sodium or other pyraphoric materials will require special extinguishing agents such as dry sand, soda ash, graphite, or sodium chloride. Extingurshmg agents andlor extinguishers should be provided if such materials a e used. Automatic extinguishing systems for pyraphorie materials wauld be very rare and not likely to be needed in any ordinary hospital laboratory. Water, carbon dioxide, and dry chemical extinguishers or aystemv would protect the containers and ~olvents of anv uvrmhoric chemicals " which might he used in small quantities. Turning now to consideration of fixed autamntie extinguishing systems for laboratories, the author has seen laboratories in which large quantities of flammable solvents in glass and metal con(Continued on page A6S8)
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severe enough to damage the struct,nre of the building unless it could be controlled by an automatic extinguishing system. There me usually so many sources of hot ignition in a laboratory-flames, equipment, electrical switches, motors, stdic-that vapors from pouring or a broken bottle of flammsble liquid are almost certain to catch fire rtnd spread to other cans and bottles on open shelves. The most economical autometio fire extinguishing system to install, maintain, and operate is an ant,omatic sprinkle? system. An automatic sprinkler system consists of water supply piping to a series of openings which are plugged with devices which open individuallv when they are
heated by fire to preselected temperatures such a s 165°F. (Sprinkler fiystems also discharge water if pipes are allowed to freeze or the system is damaged by mechanical equipment.) When .a fire heats a sprinkler head enough to melt its fusible plug or soldered linkage, water comes out of the opening and strikes a deflector which makes a rain-like spray to wet and cool burning material. The spray is less dense than a bnt,hroom shower and is not likely to extinguish all solvent fires or fires under t,ables or shelves. Therefore in case of fire the hospital fire brigade or the public fire deparbment should expect to enter the roam with self-contained breathing rtppsrstus and complete the extinguishment. Sprinkler systems, except one type, do not turn ON the water sutometicslly after afire so that the system will have to be shut ON manually to replace heads which apened-hut only when the fire depart-
Table 1 Flammable Liquid Pro~ertiesand Container Limits
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rnent has the fire out and gives approval. If s sprinkler system discharges because of freeaing or mechanical damage, turn off the system for repaim and prampt,ly notify the fire department and your insurance company. Automatic extinguishing systems which use carbon dioxide, dry chemicsl, or halogenated agent? (hdons) are available for spot application or total flooding. Such systems are installed for special or severe hazards, and are usually supplemented by an automstie sprinkler system, which does not have a. limited quantity of extinguishing agent as the specialsystems do. Spot application systems are used for localized hazards such as a hulk transfer of solvent from drums to kettles or lines t o tanks. T u t d flooding systems me used for relatively small rooms with severe hazards. Some examples of applications of special extinguishing systems include the following: Halon flooding systems: computer facility, aircraft manufacture & repair; carbon dioxide spot system?: paint mill rtnd kettle charging, solvent costing machines; carbon dioxide flooding systems: adhesives bulk mixing rooms, research pilot plant; dry chemical spot systems: kitchen range ducts, painting contractor storage; dry chemical flooding systems: research laboratory hoods; high expansion foam systems: tire warehouse; automatic sprinkler .systems: flammable liquid stockrooms, flammahle liquid drum warehouses, indwtrial research laboratories.
Table 2
Hazard Ratings of Clinical Laboratory Chemicals
Chemical name
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------EmergencyHeslth Fire Instability haaard hazard hazard rating rating rating
Acetic acid., zlaoisl Acetone Benzene Carbon tetrachloride Dioxane Ethyl ether Hydrocgoric, acid Perchlarlc acid, 70-72%
2
Picric acid Sodium Sodium hydroxide Sulfuric add
2 3 3 3
Special hamrdds
2
Forms peroxides Forms peroxides
4 1 0 0
Carbon dioxide and halon flooding systems require automatic closing of doors and windows and ventilation shutdown, and carbon dioxide systems frequently have elarms and discharge delays so personnel e m leave the area before the rarbon dioxide concentration builds up. If laboratory or storage areas have comhust.ihle fire loads that must have automatic extinguishing systems, automatic sprinkler systems have the advantages of safet,y, lowest cost, and broadest general effectiveness. Flammable a n d Combustible Liquids The next major section of the Standard det,ails requirements for handling flammable and combustible liquids and for disposing of hazmdous materida. Considerable attention is given to limiting container sizes and quantities stored in t,he laboratory because of the severe fire basmds of flammable liquids and the concentrated fire load that can xesult from flammable and combustible liquids. As an extlmple, full-scale simulrttion of 8. laboratory fire with ignition of a l-gal spill of flammable liquid produced s. room temperature of nearly 1,00O0F within 1 mi". Container Limitations Size limitations for glass containers and approved plastic containers are based on the flash point ?nd bailing point of the flammable liquid, ranging from 500 ml or 1pt for ethyl ether up to 1 gal for xylene. One-gal safety cans are allowed for any flammable liquid. A safety can has a spring-loaded lid wbich prevents spills and relieves internal pressures so that the can will not rupture under fire exposure or other temperature extreme. Safety cans will hear an FM or UL marking to indicate thst prototypes have passed rigorous tests by Factory Mutusl Engineering Laboratories or Underwriters Laboratories. Table I lists some commonly-used flammable liquids and the container siee limits established by the Safety Standard far Hospital Laboratories and the NFPA Flammable and Combustible Liquids Code. The table also lists the boiling points, ignition temperatures, and flash
High exphive
Quantity Limitations The Standard specifies that laboratory practices shall limit working supplim of flammable and combustible liquids to the amount needed for 2 days, and not more than a total of 10 gal outside of storage cabinets in a laboratory of 5,000 sq ft or less in area. Up to 60 gal may be stored in an approved storage cabinet in a lahoratory; greater quantities should be stored in an approved flammable liquid storage room. Storage Cabinets The approved storage cabinet referred to in the Safety Standard for Hospital Laborrttories is defined in the NFPA Flammable Liquids Code as one that is designed to withstand a standard 10-min fire test without exceeding 3 2 5 T inside the cahinet. The Code specifies that the cabinet door will remain securely closed during the test and that the joints and seams will remain tight. One storage cabinet construction deemed in compliance with the test requirements is 1%. plywood with rabbetted joints and hinges thst artre mounted to withstand the fire test. Further construction details of this cabinet, based on tests by the Los Angeles Fire Department, are described in the NFPA Flammable and Combustible Liquids Code. Another cabinet construction deemed in compliance with the test requirements is a dauble-walled cabinet of 18-gauge sheet iron with a 2-in. sill and a 3-point door lock. This design was developed about 1927; the basis for the design is unknown. A hospital laboratory fire in Minneapolis demonstrated that ordinary bench cahinets may be able to meet the fire test requirements. The author helieves that such tests should he made so that special cabinet purchases will not be required unless necessary. Hazard Identification The NFPA has developed a numerical system for rating the relative hazards to (Continued a page A640)
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hedth, Bammahility and instability of chemicals under emergency exposure conditions such as a sprll or fire, and the Standard calls for the use of this system in hospital laboratories. Before we describe the Strtndard requirements let us explain and illmtrate the NFPA hazard identification system. Emergency health hazards, flammability hssards. and instability or reactiGity hazards a& graded an a nimerical scale ranging from zero for no unusual hazard up to four for extreme hazard. The hazard signal is in the farm of a diamond divided into four sections with the degreesof health, flammable and instability hazards always shown on the left, top center, and right. The lower quadrant is reserved for any special information needed such ss a. radiation symbol, biohazard symbol, or the symbol for water reactivity-a capital W with a horiaontal line through the letter. Color is frequently used to supplement the hazard signal, with a blue background for emergency health hazard rating, red background for flammability hazard rating, and yellow far the background of the instability hazard rating. In the "Fire Protection Guide on Hazardous Materials", third edit,ion,published by the National Fire Protection Association, the objectives of the hazard identifi. to procation system are described-". vide an appropriate signal or alert and on-the-spot information to safeguard the lives of both public and private fire fighting personnel during fire emergencies!' The system provides "readily recagnizable and easily understood markings, which will give a t a glance a general idea af the inherent hazards of any material and t,he order of severity af these hazards as they relate t o fire prevention, exposure, and control." Tahle 2 lists some clinical laboratory chemicak and the hazard ratings listed in the NFPA publication "Fire Protection Guide on Hazardous Mrtterids", which can he obtained for $5.50 from the NFPA a t 60 Batterymarch Street, Boston, Mass. 02110. For convenient reminder of the approximate meaning of the various hazards signals, some hospital laboratories use a label or explanatory sign on laboratory doors. However, readers should realize that short statements of hazards on the sign are condensed. The full definitions in the NFPA publication should he used in training programs and for any tentative hazard signal assignments which may be made in the absence of published values. Tahle 3 presents examples of the condensed terminology and the definitions. The Ssfety Standard for Hospital Laboratories specifies that all doors !ceding t o laboratories in hospitals and other healthrelated facilities shall he marked with the hasard identiffcation system described in NFPA No. 704M-1969 and briefly outlined earlier in this article. The guide for seleoting the numbers for the h.wsrd signal sign is that for each t,ype of hasrtrd
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