Safer Design Concepts Applied to Laboratories
4
Inherently Safer Design Concepts Applied to Laboratories Amy E. Theis and Charles F. Askonas Fauske & Associates, LLC, Burr Ridge, IL 60527; [email protected] (for correspondence) Published online 23 April 2013 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/prs.11590 Several types of experiments are performed in laboratories at Fauske & Associates, LLC (FAI). Test equipment includes calorimeters to characterize reactive chemical systems and multiple instruments to characterize both combustible dust and gas/vapor explosions. It is a challenge to ensure that each project is completed safely, since a variety of chemicals are used and tested under extreme conditions. It is vital to ensure the safety of people, property, and the environment at all times. This requires first identifying the hazards (includ- ing rigorous review of material safety data sheets) and then implementing adequate engineering and administrative controls as necessary. This article will document best prac- tices including management commitment, predicting and eliminating hazards during extreme test conditions, and implementing inherently safer design concepts to laboratory testing. V C 2013 American Institute of Chemical Engineers Process Saf Prog 32: 142–145, 2013 Keywords: laboratory safety; hazard identification; inher- ently safer design (ISD); MSDS Review. INTRODUCTION The focus of this article will be to show experimenters how to design and execute hazardous tests, such as calorim- etry testing, flammability testing, and dust explosion testing. The principles could be applied to any laboratory scale test- ing. Dust testing services typically involve performing the same procedures on a variety of different chemicals. For this type of testing, the material safety data sheet (MSDS) is the most important safety document to review. Calorimetry test- ing and flammability testing involve customized test proce- dures on a variety of different chemicals. These tests typically require a more thorough safety review. As a laboratory that provides process safety information, it is common to perform testing to understand the reactive chemistry, and combustible characteristics of flammable dust and vapors. A key component of laboratory safety is predicting possible consequences (temperature, pressure, corrosivity, and toxicity) based on test conditions for the experiment. It is a misconceived notion that small-scale test- ing means small-scale hazards. This is not true and can lead one to a false sense of security. Prior to each test campaign, a hazard identification process must be conducted in order to determine an appropriate hazard control strategy utilizing inherently safer design concepts to ensure that personnel, equipment, and property are adequately protected [10]. MANAGEMENT COMMITMENT It is essential that a safety culture is established and emphasized by top-level management. It is FAI company policy to employ a safety first principle for all jobs with no exceptions. This directive is reinforced by the highest level of management and is engrained in the company culture. Management is committed to providing each employee with the appropriate equipment and resources to maintain safe working conditions. This safety directive is given by the Pres- ident, reiterated by management, and communicated to all employees at regular department meetings. Each employee is given an opportunity to express workplace safety concerns during these meetings or directly to their supervisor at any time. This input is taken seriously by management, assigning action items/due dates to responsible personnel in order to address and resolve concerns. No job is performed without understanding the safety concerns and ensuring that the appropriate equipment and facilities are available. HAZARD IDENTIFICATION AND ASSESSMENT The hazards of a chemical or intended chemistry must first be identified. Several resources are available to identify and assess hazards of chemicals [1,2] as well as hazards due to chemical interactions [3]. The hazard identification process begins with an MSDS review for each chemical that is to be used for testing. It is recommended to obtain the MSDS from the original manufacturer, since these tend to be most com- plete and provide the most detail. The following is a list of tips to ensure thorough MSDS review. MSDS Review Checklist 1. Volatility 2. Toxicity including health hazards and routes of entry 3. Corrosive properties 4. Reactivity with air, water or moisture 5. Unique properties 6. Verify safety information from more than one source. The most conservative information should be used to develop safe handling and test procedures 7. N/A means not available. Contact the technical support of the manufacturer for more information In some cases, the MSDS for a chemical does not provide enough information for an appropriate safety review. This can be due to many reasons. If the hazards identification sec- tion is brief or limited, a call to the technical support person of the manufacturer is recommended in order to understand the material better. The composition of the material with the identification of the chemicals (and CAS numbers if V C 2013 American Institute of Chemical Engineers 142 June 2013 Process Safety Progress (Vol.32, No.2)
description
Safer Design Concepts Applied to Laboratories
Transcript of Safer Design Concepts Applied to Laboratories
Inherently Safer Design Concepts Applied to
LaboratoriesAmy E Theis and Charles F AskonasFauske amp Associates LLC Burr Ridge IL 60527 theisfauskecom (for correspondence)
Published online 23 April 2013 in Wiley Online Library (wileyonlinelibrarycom) DOI 101002prs11590
Several types of experiments are performed in laboratoriesat Fauske amp Associates LLC (FAI) Test equipment includescalorimeters to characterize reactive chemical systems andmultiple instruments to characterize both combustible dustand gasvapor explosions It is a challenge to ensure thateach project is completed safely since a variety of chemicalsare used and tested under extreme conditions It is vital toensure the safety of people property and the environment atall times This requires first identifying the hazards (includ-ing rigorous review of material safety data sheets) and thenimplementing adequate engineering and administrativecontrols as necessary This article will document best prac-tices including management commitment predicting andeliminating hazards during extreme test conditions andimplementing inherently safer design concepts to laboratorytesting VC 2013 American Institute of Chemical Engineers Process
Saf Prog 32 142ndash145 2013
Keywords laboratory safety hazard identification inher-ently safer design (ISD) MSDS Review
INTRODUCTION
The focus of this article will be to show experimentershow to design and execute hazardous tests such as calorim-etry testing flammability testing and dust explosion testingThe principles could be applied to any laboratory scale test-ing Dust testing services typically involve performing thesame procedures on a variety of different chemicals For thistype of testing the material safety data sheet (MSDS) is themost important safety document to review Calorimetry test-ing and flammability testing involve customized test proce-dures on a variety of different chemicals These teststypically require a more thorough safety review
As a laboratory that provides process safety informationit is common to perform testing to understand the reactivechemistry and combustible characteristics of flammable dustand vapors A key component of laboratory safety ispredicting possible consequences (temperature pressurecorrosivity and toxicity) based on test conditions for theexperiment It is a misconceived notion that small-scale test-ing means small-scale hazards This is not true and can leadone to a false sense of security Prior to each test campaigna hazard identification process must be conducted in orderto determine an appropriate hazard control strategy utilizinginherently safer design concepts to ensure that personnelequipment and property are adequately protected [10]
MANAGEMENT COMMITMENT
It is essential that a safety culture is established andemphasized by top-level management It is FAI companypolicy to employ a safety first principle for all jobs with noexceptions This directive is reinforced by the highest levelof management and is engrained in the company cultureManagement is committed to providing each employee withthe appropriate equipment and resources to maintain safeworking conditions This safety directive is given by the Pres-ident reiterated by management and communicated to allemployees at regular department meetings Each employeeis given an opportunity to express workplace safety concernsduring these meetings or directly to their supervisor at anytime This input is taken seriously by management assigningaction itemsdue dates to responsible personnel in order toaddress and resolve concerns No job is performed withoutunderstanding the safety concerns and ensuring that theappropriate equipment and facilities are available
HAZARD IDENTIFICATION AND ASSESSMENT
The hazards of a chemical or intended chemistry mustfirst be identified Several resources are available to identifyand assess hazards of chemicals [12] as well as hazards dueto chemical interactions [3] The hazard identification processbegins with an MSDS review for each chemical that is to beused for testing It is recommended to obtain the MSDS fromthe original manufacturer since these tend to be most com-plete and provide the most detail The following is a list oftips to ensure thorough MSDS review
MSDS Review Checklist
1 Volatility2 Toxicity including health hazards and routes of entry3 Corrosive properties4 Reactivity with air water or moisture5 Unique properties6 Verify safety information from more than one source The
most conservative information should be used to developsafe handling and test procedures
7 NA means not available Contact the technical supportof the manufacturer for more information
In some cases the MSDS for a chemical does not provideenough information for an appropriate safety review Thiscan be due to many reasons If the hazards identification sec-tion is brief or limited a call to the technical support personof the manufacturer is recommended in order to understandthe material better The composition of the material with theidentification of the chemicals (and CAS numbers ifVC 2013 American Institute of Chemical Engineers
142 June 2013 Process Safety Progress (Vol32 No2)
available) is important Vague descriptions such as ldquo90 sol-ventinert 10 reactive materialrdquo do not provide enough in-formation to determine the hazard of the material A materialthat is inert according to the manufacturer does not meanthat it could not decompose react or form a corrosive mate-rial when exposed to elevated temperatures If the materialis a solvent it must have a boiling point density and otherphysical properties that need to be identified prior to testingFor a material in development test data may be limited ornot available Contacting the chemist (or technical supportperson) at the manufacturer is helpful because they canindicate generally whether it is acidic basic or neutral Insome cases testing may not have yet been performed on thematerial so they cannot provide specific ranges for flammablelimits but some general information may be available It isnot safe to assume that NA means ldquoNot Applicablerdquo It typi-cally means ldquoNot Availablerdquo and further investigation is neces-sary If information cannot be obtained the test is designed tominimize or eliminate the hazard if it should be present
Information regarding exposure controls are reviewedand compared with information provided in the NIOSHpocket guide [4] If an MSDS for an exact chemical matchcannot be found the MSDS for a chemical with the samestructure or functional groups can be used as a referenceThe most conservative values are used for the test designPersonal protective equipment (PPE) required by the MSDSare used at a minimum In some cases additional pieces ofPPE are selected for an increased level of protection
The MSDS specifies the suitable fire extinguishing mediarequired for the chemical This should be readily available inthe laboratory while tests are being performed Proper PPEshould be worn in case of an accidental release or spillAppropriate clean-up equipment and procedures should bereadily available and personnel should understand the pro-cedures to follow if a spill should occur For instance whenstrong acids are used a bucket of water with baking soda orcaustic is readily available to neutralize a chemical spill
Appropriate handling and storage conditions for the mate-rial should be followed Information regarding storage sta-bility reactivity and proper disposal conditions is alsoimportant The MSDS should also indicate materials to avoidThe chemical incompatibilities can be used to determine suit-able materials for testing
The National Fire Protection Association (NFPA) hasdeveloped a system for indicating the health flammabilityreactivity and special hazards for many common chemicalsthrough use of the NFPA 704 Diamond Ratings for healthflammability and reactivity range from 0 (no hazard) to 4(most hazardous) These ratings apply only to the individualchemicals not to a mixture of chemicals Additional informa-tion beyond the individual NFPA ratings is needed to identifythe hazards associated with the chemicals and test conditionsfor a proposed experiment
Another resource for chemical information is the CoastGuard Chemical Hazards Response Information System(CHRIS) [5] which provides chemical physical thermody-namic toxicological and fire properties for more than 1000chemicals This information serves as an excellent supple-ment to the MSDS
In addition to the MSDS a chemical test questionnaire isrequired for calorimetry testing This contains critical infor-mation including the test recipe (composition) test condi-tions and procedure chemical structures of reactantsstoichiometry for the expected reaction material incompati-bilities and possible decomposition products Hazard identi-fication of chemicals (reactants intermediates and products)and the expected or possible chemistryreactions is crucial todeveloping an appropriate control strategy The possibledecomposition products are important to understand
because these can be generated if high temperatures areexperienced during the test By examining the functionalgroups of the raw materials possible decomposition prod-ucts are predicted using organic chemistry reaction mecha-nisms [6] Elevated temperatures during testing can lead toelevated pressures that could then lead to unwanted decom-position or side reactions that should be anticipated beforetesting is performed Likely functional groups leading toenergetic decompositions should be given special attention[7] In these cases the peak pressure is estimated for a speci-fied amount of sample in a given reaction vessel to ensurethat it can be safely accommodated
It is also necessary to determine the amount of chemicalto be handled or released exposure limits (skin and inhala-tion) [4] US Department of Transportation (DOT) hazardclass and Poison Inhalation Hazard (PIH) zone [8] flamma-bleexplosion properties and boiling pointvapor pressuredata (for gas or liquid)
The quantity of material handled or released directlyimpacts the hazard associated with the process For instancesome tests require only a few grams of material while sometests require several hundred grams However for highlytoxic materials even a few grams of material may requirespecial handling procedures and high supervision or evacua-tion of the area to limit exposure to personnel The quantityof material affects the handling approaches and controlmeasures required for handling a chemical
The DOT PIH zone is a useful index for determining thetoxicity of a material (see Figure 1) [8] Classifications are AB C or D with A being the highest and D being the lowestFor gases the PIH zone is a function of the inhalation toxic-ity For liquids the volatility (vapor concentration) and thelethal concentration are factored into assigning the hazardzone Careful attention is given to test campaigns that utilizechemicals in DOT hazard class 23 that are poisonous gases
Learning from past experiments is invaluable Providingprocess safety data to industry for more than 25 years hasresulted in several thousands of experiments being per-formed in our laboratories This experience can be used to
Figure 1 US DOT poison inhalation hazard zones forliquids and gases [Color figure can be viewed in the onlineissue which is available at wileyonlinelibrarycom]
Process Safety Progress (Vol32 No2) Published on behalf of the AIChE DOI 101002prs June 2013 143
predict or anticipate possible test conditions includingmaximum temperature pressure material compatibilityequipment problems decomposition temperature samplebehavior (tendency for foaming etc) and general lessonslearned Any experience the client has performing tests withthis chemistry on the bench top is also useful Adiabatic datais more conservative than bench top data It is typical for ad-iabatic experiments to yield higher temperatures and higherpressures as well as higher rates of temperature and pressurerise compared to bench scale testing
HAZARD CONTROL
In order to ensure that proper measures are taken tosafely perform testing and accommodate all decompositionproducts a detailed hazard review is performed on identifiedhazards Inherently safer design methodologies of minimiza-tion substitution moderation and simplification are used tomanage or control the hazard These are applied to both en-gineering controls and administrative controls (includingPPE)
Engineering controls are the first line of defense againsthazards This includes proper ventilation to minimize person-nel exposure to hazardous materials NFPA 45 [9] can beused for specific guidance on this and other design-relatedissues Ventilation can be accomplished using a laboratoryfume hood For smaller quantities a local ventilation vacuumsystem can be used Flammability testing should be per-formed in a concrete bunker and equipment can be instru-mented to operate remotely if it is necessary Choosing alocation that can safely accommodate the anticipated hazardsfor raw materials intermediates desired and decompositionproducts from an experiment is important to maintainemployee and workplace safety For highly toxic materials(eg hydrogen cyanide) on-site testing is performed at acustomer facility
Proper equipment selection is an example of an engineer-ing control Choosing a test cell material that is compatiblewith the reactants products and potential decompositionproducts is critical to maintaining safe working conditionsreducing undesired side reactions and ensuring successfulcompletion of the experiment If a material is corrosive tostainless steel Hastelloy can be substituted to protect againstcorrosion The material of the vessel should also be able towithstand the expected maximum pressure of a test or havea relief path installed to safely relieve the accumulatedpressure
If a sample is reactive with oxygen or air the test cell willbe purged with nitrogen in order to reduce the initial oxygenconcentration in the system An alternative would be to han-dle the material in a glove box with nitrogen atmosphere
Performing an experiment with a smaller amount of sam-ple is an example of minimizing the hazard For instance asmaller size test apparatus such as the Advanced ReactiveSystem Screening Tool (ARSST 10 mL of sample in 350-mLcontainment) can be used instead of the Vent Sizing Package(VSP2 80 mL of sample in 4-L containment) for a toxic gassysystem where hydrogen sulfide could possibly be generatedThe ARSST has also been successfully used to minimize thequantity of toxic raw materials such as hydrazine hydrate Ifa customer is not familiar with the chemistry a screening test[typically by Differential Scanning Calorimetry (DSC) using ahigh-pressure crucible] can be performed to characterize thematerial
PPE is a key component to minimize personnel exposureto a hazard The required PPE depends on the quantity ofmaterial being handled or generated PPE includes eyefaceprotection handbody protection ear and inhalation protec-tion (respirators) Typically the minimum requirement fortesting is safety glasses lab coat and nitrile gloves After
review of the MSDS additional protection such as goggles(for acids or bases) face shield TyvekVR suit (for strong skinirritants) half or full face respirator or other PPE may bedeemed necessary In cases where filtering cartridges are noteffective a supplied air respirator is used The supervisorreviews the required PPE with the test personnel prior to theexperiment to ensure they are comfortable wearing andproperly using the equipment as well as understanding thehazard posed by the chemical(s) In cases where PPE is bur-den-some to wear (eg self-contained breathing apparatus)the required amount of time to wear the equipment is mini-mized (if possible) In some cases two people are assignedto a particular task to create a ldquobuddy systemrdquo
For highly toxic materials (chlorine gas or ethylene ox-ide) the quantities of raw materials are limited to only thenecessary amount This can mean ordering the minimumamount of material to be used for testing Another strategywould be to meter in a raw material instead of performing abatch addition to minimize the material contact and there-fore heat or pressure generation Another protective strategyfor highly toxic chemicals includes procedural controls tominimize personnel exposure Handling guidelines andrestrictions have been developed that define safe handlingand disposal procedures for these types of chemicals
Substitution is another inherently safer concept that canbe applied for the safe handling of chemicals in thelaboratory Typically the chemistry to be performed is notflexible However it is possible to substitute a differentchemical for cleaning One example is using baking sodaand water solution for cleaning instead of caustic Forstrongly acidic chemicals caustic is necessary and appropri-ate If the potential acidic product is mild then baking sodaand water is sufficient The hazard control measure shouldbe proportional to the identified hazard
Another consideration for inherently safer handling achemical is moderating the effect of a material One way toaccomplish this is to use a dilute solution instead of a stron-ger one Neutralization procedures are implemented whenpoisonous gases are suspected to be formed which limitspersonnel exposure minimizes the quantity and reduces thetoxicity of the released material
For a reaction that is expected to generate anoncondensable gas the headspace volume of the test maybe increased in order to moderate the pressure rise rate Thiscould be accomplished by performing an ARSST experimentinstead of a VSP2 experiment as previously mentioned or byperforming an open system VSP2 test (4-L headspace) insteadof a closed VSP2 test (0040-L headspace) The expected pres-sure of a test is calculated based on any expected pressuregeneration as well as the vapor pressure of the mixture giventhe expected temperature range of the experiment This infor-mation is used to determine the proper selection of contain-menttest vessel required pressure of nitrogen supply andemergency test shut down procedures if necessary
Controlling the hazard can utilize the inherent safer con-cept of simplification One example is to reduce the numberof fittings in the test apparatus to minimize the potential forleaks Other considerations for simplification include the testequipment as well as handling and disposal of the chemicalEfforts are made to handle chemicals as close to room tem-perature as possible Some tests require subambient or ele-vated temperatures In these cases administrative controls(procedures) and PPE are used to ensure personnel safety
An active engineering control is to specify shut down cri-teria in the software program This would be for situationswhere the outcome is well understood Some equipment orexperiments may require additional supervision if the chem-istry is not well defined or if consequences due to a devia-tion in the operations could be highly hazardous
DOI 101002prs Process Safety Progress (Vol32 No2)144 June 2013 Published on behalf of the AIChE
Appropriate control strategies are identified in test proce-dures that serve as administrative controls Other administra-tive controls include safe handling procedures for uniquechemicals such as compressed or corrosive liquids and acidgases
CONCLUSIONS
Test personnel should be prepared to safely accommo-date and dispose of all foreseeable reaction and decomposi-tion products Identifying the hazards given the reactantstest conditions and expected desired and potential decom-position products is critical The required test equipmentPPE and test procedures must be identified to perform thetest disassemble the apparatus and dispose of all materialssafely In summary the components for maintaining a safework environment include a safety culture established andvalued by management diligent hazard identification anddeveloping a hazard control strategy utilizing inherently saferdesign concepts
LITERATURE CITED
1 DJ Leggett Identifying hazards in the chemical researchlaboratory Process Saf Prog 31 (2012) 393ndash397
2 S Dharmavaram and JA Klein An introduction toassessing process hazards Process Saf Prog 31 (2012)266ndash270
3 EM Davis J Murphy D Silva The CCPS chemicalreactivity evaluation tool Process Saf Prog 31 (2012)203ndash218
4 National Institute for Occupational Health and Safety(NIOSH) Pocket Guide to Chemical Hazards Departmentof Health and Human Services September 2007 Avail-able at wwwcdcgovniosh (accessed February 262013)
5 CHRIS (USCG) ldquoChemical Hazards Response InformationSystem Hazard Chemical Data Manualrdquo CommandmentInstruction Manual M1646512C US Department ofTransportation United States Coast Guard 1999 Avail-able at httpwwwuscgmildirectivescim16000-16999CIM_16465_12Cpdf (accessed March 22 2013)
6 A Streitwieser and C Heathcock Introduction to OrganicChemistry 2nd ed Macmillan New York 1981
7 Parr Instrument Company Instruction Manuals 230MSafety in the Operation of Reactors and Pressure VesselsAvailable at httpwwwparrinstcomsupportdownloadsmanuals230M_Parr_Safety-Lab-Reactorspdf (accessed February 9 2012)
8 Code of Federal Regulations Pipeline and HazardousMaterials Safety Administration (Department of Transpor-tation) 49CFR Parts 171ndash173 (2012)
9 NFPA 45 Fire Protection for Laboratories Using Chemi-cals 2011 edition National Fire Proctection AssociationQuincy 2010
10 AE Theis and CF Askonas Maintain Safety Excellencein Laboratory Facilities AIChE Global Congress on Pro-cess Safety Paper 79a 2012
Process Safety Progress (Vol32 No2) Published on behalf of the AIChE DOI 101002prs June 2013 145
available) is important Vague descriptions such as ldquo90 sol-ventinert 10 reactive materialrdquo do not provide enough in-formation to determine the hazard of the material A materialthat is inert according to the manufacturer does not meanthat it could not decompose react or form a corrosive mate-rial when exposed to elevated temperatures If the materialis a solvent it must have a boiling point density and otherphysical properties that need to be identified prior to testingFor a material in development test data may be limited ornot available Contacting the chemist (or technical supportperson) at the manufacturer is helpful because they canindicate generally whether it is acidic basic or neutral Insome cases testing may not have yet been performed on thematerial so they cannot provide specific ranges for flammablelimits but some general information may be available It isnot safe to assume that NA means ldquoNot Applicablerdquo It typi-cally means ldquoNot Availablerdquo and further investigation is neces-sary If information cannot be obtained the test is designed tominimize or eliminate the hazard if it should be present
Information regarding exposure controls are reviewedand compared with information provided in the NIOSHpocket guide [4] If an MSDS for an exact chemical matchcannot be found the MSDS for a chemical with the samestructure or functional groups can be used as a referenceThe most conservative values are used for the test designPersonal protective equipment (PPE) required by the MSDSare used at a minimum In some cases additional pieces ofPPE are selected for an increased level of protection
The MSDS specifies the suitable fire extinguishing mediarequired for the chemical This should be readily available inthe laboratory while tests are being performed Proper PPEshould be worn in case of an accidental release or spillAppropriate clean-up equipment and procedures should bereadily available and personnel should understand the pro-cedures to follow if a spill should occur For instance whenstrong acids are used a bucket of water with baking soda orcaustic is readily available to neutralize a chemical spill
Appropriate handling and storage conditions for the mate-rial should be followed Information regarding storage sta-bility reactivity and proper disposal conditions is alsoimportant The MSDS should also indicate materials to avoidThe chemical incompatibilities can be used to determine suit-able materials for testing
The National Fire Protection Association (NFPA) hasdeveloped a system for indicating the health flammabilityreactivity and special hazards for many common chemicalsthrough use of the NFPA 704 Diamond Ratings for healthflammability and reactivity range from 0 (no hazard) to 4(most hazardous) These ratings apply only to the individualchemicals not to a mixture of chemicals Additional informa-tion beyond the individual NFPA ratings is needed to identifythe hazards associated with the chemicals and test conditionsfor a proposed experiment
Another resource for chemical information is the CoastGuard Chemical Hazards Response Information System(CHRIS) [5] which provides chemical physical thermody-namic toxicological and fire properties for more than 1000chemicals This information serves as an excellent supple-ment to the MSDS
In addition to the MSDS a chemical test questionnaire isrequired for calorimetry testing This contains critical infor-mation including the test recipe (composition) test condi-tions and procedure chemical structures of reactantsstoichiometry for the expected reaction material incompati-bilities and possible decomposition products Hazard identi-fication of chemicals (reactants intermediates and products)and the expected or possible chemistryreactions is crucial todeveloping an appropriate control strategy The possibledecomposition products are important to understand
because these can be generated if high temperatures areexperienced during the test By examining the functionalgroups of the raw materials possible decomposition prod-ucts are predicted using organic chemistry reaction mecha-nisms [6] Elevated temperatures during testing can lead toelevated pressures that could then lead to unwanted decom-position or side reactions that should be anticipated beforetesting is performed Likely functional groups leading toenergetic decompositions should be given special attention[7] In these cases the peak pressure is estimated for a speci-fied amount of sample in a given reaction vessel to ensurethat it can be safely accommodated
It is also necessary to determine the amount of chemicalto be handled or released exposure limits (skin and inhala-tion) [4] US Department of Transportation (DOT) hazardclass and Poison Inhalation Hazard (PIH) zone [8] flamma-bleexplosion properties and boiling pointvapor pressuredata (for gas or liquid)
The quantity of material handled or released directlyimpacts the hazard associated with the process For instancesome tests require only a few grams of material while sometests require several hundred grams However for highlytoxic materials even a few grams of material may requirespecial handling procedures and high supervision or evacua-tion of the area to limit exposure to personnel The quantityof material affects the handling approaches and controlmeasures required for handling a chemical
The DOT PIH zone is a useful index for determining thetoxicity of a material (see Figure 1) [8] Classifications are AB C or D with A being the highest and D being the lowestFor gases the PIH zone is a function of the inhalation toxic-ity For liquids the volatility (vapor concentration) and thelethal concentration are factored into assigning the hazardzone Careful attention is given to test campaigns that utilizechemicals in DOT hazard class 23 that are poisonous gases
Learning from past experiments is invaluable Providingprocess safety data to industry for more than 25 years hasresulted in several thousands of experiments being per-formed in our laboratories This experience can be used to
Figure 1 US DOT poison inhalation hazard zones forliquids and gases [Color figure can be viewed in the onlineissue which is available at wileyonlinelibrarycom]
Process Safety Progress (Vol32 No2) Published on behalf of the AIChE DOI 101002prs June 2013 143
predict or anticipate possible test conditions includingmaximum temperature pressure material compatibilityequipment problems decomposition temperature samplebehavior (tendency for foaming etc) and general lessonslearned Any experience the client has performing tests withthis chemistry on the bench top is also useful Adiabatic datais more conservative than bench top data It is typical for ad-iabatic experiments to yield higher temperatures and higherpressures as well as higher rates of temperature and pressurerise compared to bench scale testing
HAZARD CONTROL
In order to ensure that proper measures are taken tosafely perform testing and accommodate all decompositionproducts a detailed hazard review is performed on identifiedhazards Inherently safer design methodologies of minimiza-tion substitution moderation and simplification are used tomanage or control the hazard These are applied to both en-gineering controls and administrative controls (includingPPE)
Engineering controls are the first line of defense againsthazards This includes proper ventilation to minimize person-nel exposure to hazardous materials NFPA 45 [9] can beused for specific guidance on this and other design-relatedissues Ventilation can be accomplished using a laboratoryfume hood For smaller quantities a local ventilation vacuumsystem can be used Flammability testing should be per-formed in a concrete bunker and equipment can be instru-mented to operate remotely if it is necessary Choosing alocation that can safely accommodate the anticipated hazardsfor raw materials intermediates desired and decompositionproducts from an experiment is important to maintainemployee and workplace safety For highly toxic materials(eg hydrogen cyanide) on-site testing is performed at acustomer facility
Proper equipment selection is an example of an engineer-ing control Choosing a test cell material that is compatiblewith the reactants products and potential decompositionproducts is critical to maintaining safe working conditionsreducing undesired side reactions and ensuring successfulcompletion of the experiment If a material is corrosive tostainless steel Hastelloy can be substituted to protect againstcorrosion The material of the vessel should also be able towithstand the expected maximum pressure of a test or havea relief path installed to safely relieve the accumulatedpressure
If a sample is reactive with oxygen or air the test cell willbe purged with nitrogen in order to reduce the initial oxygenconcentration in the system An alternative would be to han-dle the material in a glove box with nitrogen atmosphere
Performing an experiment with a smaller amount of sam-ple is an example of minimizing the hazard For instance asmaller size test apparatus such as the Advanced ReactiveSystem Screening Tool (ARSST 10 mL of sample in 350-mLcontainment) can be used instead of the Vent Sizing Package(VSP2 80 mL of sample in 4-L containment) for a toxic gassysystem where hydrogen sulfide could possibly be generatedThe ARSST has also been successfully used to minimize thequantity of toxic raw materials such as hydrazine hydrate Ifa customer is not familiar with the chemistry a screening test[typically by Differential Scanning Calorimetry (DSC) using ahigh-pressure crucible] can be performed to characterize thematerial
PPE is a key component to minimize personnel exposureto a hazard The required PPE depends on the quantity ofmaterial being handled or generated PPE includes eyefaceprotection handbody protection ear and inhalation protec-tion (respirators) Typically the minimum requirement fortesting is safety glasses lab coat and nitrile gloves After
review of the MSDS additional protection such as goggles(for acids or bases) face shield TyvekVR suit (for strong skinirritants) half or full face respirator or other PPE may bedeemed necessary In cases where filtering cartridges are noteffective a supplied air respirator is used The supervisorreviews the required PPE with the test personnel prior to theexperiment to ensure they are comfortable wearing andproperly using the equipment as well as understanding thehazard posed by the chemical(s) In cases where PPE is bur-den-some to wear (eg self-contained breathing apparatus)the required amount of time to wear the equipment is mini-mized (if possible) In some cases two people are assignedto a particular task to create a ldquobuddy systemrdquo
For highly toxic materials (chlorine gas or ethylene ox-ide) the quantities of raw materials are limited to only thenecessary amount This can mean ordering the minimumamount of material to be used for testing Another strategywould be to meter in a raw material instead of performing abatch addition to minimize the material contact and there-fore heat or pressure generation Another protective strategyfor highly toxic chemicals includes procedural controls tominimize personnel exposure Handling guidelines andrestrictions have been developed that define safe handlingand disposal procedures for these types of chemicals
Substitution is another inherently safer concept that canbe applied for the safe handling of chemicals in thelaboratory Typically the chemistry to be performed is notflexible However it is possible to substitute a differentchemical for cleaning One example is using baking sodaand water solution for cleaning instead of caustic Forstrongly acidic chemicals caustic is necessary and appropri-ate If the potential acidic product is mild then baking sodaand water is sufficient The hazard control measure shouldbe proportional to the identified hazard
Another consideration for inherently safer handling achemical is moderating the effect of a material One way toaccomplish this is to use a dilute solution instead of a stron-ger one Neutralization procedures are implemented whenpoisonous gases are suspected to be formed which limitspersonnel exposure minimizes the quantity and reduces thetoxicity of the released material
For a reaction that is expected to generate anoncondensable gas the headspace volume of the test maybe increased in order to moderate the pressure rise rate Thiscould be accomplished by performing an ARSST experimentinstead of a VSP2 experiment as previously mentioned or byperforming an open system VSP2 test (4-L headspace) insteadof a closed VSP2 test (0040-L headspace) The expected pres-sure of a test is calculated based on any expected pressuregeneration as well as the vapor pressure of the mixture giventhe expected temperature range of the experiment This infor-mation is used to determine the proper selection of contain-menttest vessel required pressure of nitrogen supply andemergency test shut down procedures if necessary
Controlling the hazard can utilize the inherent safer con-cept of simplification One example is to reduce the numberof fittings in the test apparatus to minimize the potential forleaks Other considerations for simplification include the testequipment as well as handling and disposal of the chemicalEfforts are made to handle chemicals as close to room tem-perature as possible Some tests require subambient or ele-vated temperatures In these cases administrative controls(procedures) and PPE are used to ensure personnel safety
An active engineering control is to specify shut down cri-teria in the software program This would be for situationswhere the outcome is well understood Some equipment orexperiments may require additional supervision if the chem-istry is not well defined or if consequences due to a devia-tion in the operations could be highly hazardous
DOI 101002prs Process Safety Progress (Vol32 No2)144 June 2013 Published on behalf of the AIChE
Appropriate control strategies are identified in test proce-dures that serve as administrative controls Other administra-tive controls include safe handling procedures for uniquechemicals such as compressed or corrosive liquids and acidgases
CONCLUSIONS
Test personnel should be prepared to safely accommo-date and dispose of all foreseeable reaction and decomposi-tion products Identifying the hazards given the reactantstest conditions and expected desired and potential decom-position products is critical The required test equipmentPPE and test procedures must be identified to perform thetest disassemble the apparatus and dispose of all materialssafely In summary the components for maintaining a safework environment include a safety culture established andvalued by management diligent hazard identification anddeveloping a hazard control strategy utilizing inherently saferdesign concepts
LITERATURE CITED
1 DJ Leggett Identifying hazards in the chemical researchlaboratory Process Saf Prog 31 (2012) 393ndash397
2 S Dharmavaram and JA Klein An introduction toassessing process hazards Process Saf Prog 31 (2012)266ndash270
3 EM Davis J Murphy D Silva The CCPS chemicalreactivity evaluation tool Process Saf Prog 31 (2012)203ndash218
4 National Institute for Occupational Health and Safety(NIOSH) Pocket Guide to Chemical Hazards Departmentof Health and Human Services September 2007 Avail-able at wwwcdcgovniosh (accessed February 262013)
5 CHRIS (USCG) ldquoChemical Hazards Response InformationSystem Hazard Chemical Data Manualrdquo CommandmentInstruction Manual M1646512C US Department ofTransportation United States Coast Guard 1999 Avail-able at httpwwwuscgmildirectivescim16000-16999CIM_16465_12Cpdf (accessed March 22 2013)
6 A Streitwieser and C Heathcock Introduction to OrganicChemistry 2nd ed Macmillan New York 1981
7 Parr Instrument Company Instruction Manuals 230MSafety in the Operation of Reactors and Pressure VesselsAvailable at httpwwwparrinstcomsupportdownloadsmanuals230M_Parr_Safety-Lab-Reactorspdf (accessed February 9 2012)
8 Code of Federal Regulations Pipeline and HazardousMaterials Safety Administration (Department of Transpor-tation) 49CFR Parts 171ndash173 (2012)
9 NFPA 45 Fire Protection for Laboratories Using Chemi-cals 2011 edition National Fire Proctection AssociationQuincy 2010
10 AE Theis and CF Askonas Maintain Safety Excellencein Laboratory Facilities AIChE Global Congress on Pro-cess Safety Paper 79a 2012
Process Safety Progress (Vol32 No2) Published on behalf of the AIChE DOI 101002prs June 2013 145
predict or anticipate possible test conditions includingmaximum temperature pressure material compatibilityequipment problems decomposition temperature samplebehavior (tendency for foaming etc) and general lessonslearned Any experience the client has performing tests withthis chemistry on the bench top is also useful Adiabatic datais more conservative than bench top data It is typical for ad-iabatic experiments to yield higher temperatures and higherpressures as well as higher rates of temperature and pressurerise compared to bench scale testing
HAZARD CONTROL
In order to ensure that proper measures are taken tosafely perform testing and accommodate all decompositionproducts a detailed hazard review is performed on identifiedhazards Inherently safer design methodologies of minimiza-tion substitution moderation and simplification are used tomanage or control the hazard These are applied to both en-gineering controls and administrative controls (includingPPE)
Engineering controls are the first line of defense againsthazards This includes proper ventilation to minimize person-nel exposure to hazardous materials NFPA 45 [9] can beused for specific guidance on this and other design-relatedissues Ventilation can be accomplished using a laboratoryfume hood For smaller quantities a local ventilation vacuumsystem can be used Flammability testing should be per-formed in a concrete bunker and equipment can be instru-mented to operate remotely if it is necessary Choosing alocation that can safely accommodate the anticipated hazardsfor raw materials intermediates desired and decompositionproducts from an experiment is important to maintainemployee and workplace safety For highly toxic materials(eg hydrogen cyanide) on-site testing is performed at acustomer facility
Proper equipment selection is an example of an engineer-ing control Choosing a test cell material that is compatiblewith the reactants products and potential decompositionproducts is critical to maintaining safe working conditionsreducing undesired side reactions and ensuring successfulcompletion of the experiment If a material is corrosive tostainless steel Hastelloy can be substituted to protect againstcorrosion The material of the vessel should also be able towithstand the expected maximum pressure of a test or havea relief path installed to safely relieve the accumulatedpressure
If a sample is reactive with oxygen or air the test cell willbe purged with nitrogen in order to reduce the initial oxygenconcentration in the system An alternative would be to han-dle the material in a glove box with nitrogen atmosphere
Performing an experiment with a smaller amount of sam-ple is an example of minimizing the hazard For instance asmaller size test apparatus such as the Advanced ReactiveSystem Screening Tool (ARSST 10 mL of sample in 350-mLcontainment) can be used instead of the Vent Sizing Package(VSP2 80 mL of sample in 4-L containment) for a toxic gassysystem where hydrogen sulfide could possibly be generatedThe ARSST has also been successfully used to minimize thequantity of toxic raw materials such as hydrazine hydrate Ifa customer is not familiar with the chemistry a screening test[typically by Differential Scanning Calorimetry (DSC) using ahigh-pressure crucible] can be performed to characterize thematerial
PPE is a key component to minimize personnel exposureto a hazard The required PPE depends on the quantity ofmaterial being handled or generated PPE includes eyefaceprotection handbody protection ear and inhalation protec-tion (respirators) Typically the minimum requirement fortesting is safety glasses lab coat and nitrile gloves After
review of the MSDS additional protection such as goggles(for acids or bases) face shield TyvekVR suit (for strong skinirritants) half or full face respirator or other PPE may bedeemed necessary In cases where filtering cartridges are noteffective a supplied air respirator is used The supervisorreviews the required PPE with the test personnel prior to theexperiment to ensure they are comfortable wearing andproperly using the equipment as well as understanding thehazard posed by the chemical(s) In cases where PPE is bur-den-some to wear (eg self-contained breathing apparatus)the required amount of time to wear the equipment is mini-mized (if possible) In some cases two people are assignedto a particular task to create a ldquobuddy systemrdquo
For highly toxic materials (chlorine gas or ethylene ox-ide) the quantities of raw materials are limited to only thenecessary amount This can mean ordering the minimumamount of material to be used for testing Another strategywould be to meter in a raw material instead of performing abatch addition to minimize the material contact and there-fore heat or pressure generation Another protective strategyfor highly toxic chemicals includes procedural controls tominimize personnel exposure Handling guidelines andrestrictions have been developed that define safe handlingand disposal procedures for these types of chemicals
Substitution is another inherently safer concept that canbe applied for the safe handling of chemicals in thelaboratory Typically the chemistry to be performed is notflexible However it is possible to substitute a differentchemical for cleaning One example is using baking sodaand water solution for cleaning instead of caustic Forstrongly acidic chemicals caustic is necessary and appropri-ate If the potential acidic product is mild then baking sodaand water is sufficient The hazard control measure shouldbe proportional to the identified hazard
Another consideration for inherently safer handling achemical is moderating the effect of a material One way toaccomplish this is to use a dilute solution instead of a stron-ger one Neutralization procedures are implemented whenpoisonous gases are suspected to be formed which limitspersonnel exposure minimizes the quantity and reduces thetoxicity of the released material
For a reaction that is expected to generate anoncondensable gas the headspace volume of the test maybe increased in order to moderate the pressure rise rate Thiscould be accomplished by performing an ARSST experimentinstead of a VSP2 experiment as previously mentioned or byperforming an open system VSP2 test (4-L headspace) insteadof a closed VSP2 test (0040-L headspace) The expected pres-sure of a test is calculated based on any expected pressuregeneration as well as the vapor pressure of the mixture giventhe expected temperature range of the experiment This infor-mation is used to determine the proper selection of contain-menttest vessel required pressure of nitrogen supply andemergency test shut down procedures if necessary
Controlling the hazard can utilize the inherent safer con-cept of simplification One example is to reduce the numberof fittings in the test apparatus to minimize the potential forleaks Other considerations for simplification include the testequipment as well as handling and disposal of the chemicalEfforts are made to handle chemicals as close to room tem-perature as possible Some tests require subambient or ele-vated temperatures In these cases administrative controls(procedures) and PPE are used to ensure personnel safety
An active engineering control is to specify shut down cri-teria in the software program This would be for situationswhere the outcome is well understood Some equipment orexperiments may require additional supervision if the chem-istry is not well defined or if consequences due to a devia-tion in the operations could be highly hazardous
DOI 101002prs Process Safety Progress (Vol32 No2)144 June 2013 Published on behalf of the AIChE
Appropriate control strategies are identified in test proce-dures that serve as administrative controls Other administra-tive controls include safe handling procedures for uniquechemicals such as compressed or corrosive liquids and acidgases
CONCLUSIONS
Test personnel should be prepared to safely accommo-date and dispose of all foreseeable reaction and decomposi-tion products Identifying the hazards given the reactantstest conditions and expected desired and potential decom-position products is critical The required test equipmentPPE and test procedures must be identified to perform thetest disassemble the apparatus and dispose of all materialssafely In summary the components for maintaining a safework environment include a safety culture established andvalued by management diligent hazard identification anddeveloping a hazard control strategy utilizing inherently saferdesign concepts
LITERATURE CITED
1 DJ Leggett Identifying hazards in the chemical researchlaboratory Process Saf Prog 31 (2012) 393ndash397
2 S Dharmavaram and JA Klein An introduction toassessing process hazards Process Saf Prog 31 (2012)266ndash270
3 EM Davis J Murphy D Silva The CCPS chemicalreactivity evaluation tool Process Saf Prog 31 (2012)203ndash218
4 National Institute for Occupational Health and Safety(NIOSH) Pocket Guide to Chemical Hazards Departmentof Health and Human Services September 2007 Avail-able at wwwcdcgovniosh (accessed February 262013)
5 CHRIS (USCG) ldquoChemical Hazards Response InformationSystem Hazard Chemical Data Manualrdquo CommandmentInstruction Manual M1646512C US Department ofTransportation United States Coast Guard 1999 Avail-able at httpwwwuscgmildirectivescim16000-16999CIM_16465_12Cpdf (accessed March 22 2013)
6 A Streitwieser and C Heathcock Introduction to OrganicChemistry 2nd ed Macmillan New York 1981
7 Parr Instrument Company Instruction Manuals 230MSafety in the Operation of Reactors and Pressure VesselsAvailable at httpwwwparrinstcomsupportdownloadsmanuals230M_Parr_Safety-Lab-Reactorspdf (accessed February 9 2012)
8 Code of Federal Regulations Pipeline and HazardousMaterials Safety Administration (Department of Transpor-tation) 49CFR Parts 171ndash173 (2012)
9 NFPA 45 Fire Protection for Laboratories Using Chemi-cals 2011 edition National Fire Proctection AssociationQuincy 2010
10 AE Theis and CF Askonas Maintain Safety Excellencein Laboratory Facilities AIChE Global Congress on Pro-cess Safety Paper 79a 2012
Process Safety Progress (Vol32 No2) Published on behalf of the AIChE DOI 101002prs June 2013 145
Appropriate control strategies are identified in test proce-dures that serve as administrative controls Other administra-tive controls include safe handling procedures for uniquechemicals such as compressed or corrosive liquids and acidgases
CONCLUSIONS
Test personnel should be prepared to safely accommo-date and dispose of all foreseeable reaction and decomposi-tion products Identifying the hazards given the reactantstest conditions and expected desired and potential decom-position products is critical The required test equipmentPPE and test procedures must be identified to perform thetest disassemble the apparatus and dispose of all materialssafely In summary the components for maintaining a safework environment include a safety culture established andvalued by management diligent hazard identification anddeveloping a hazard control strategy utilizing inherently saferdesign concepts
LITERATURE CITED
1 DJ Leggett Identifying hazards in the chemical researchlaboratory Process Saf Prog 31 (2012) 393ndash397
2 S Dharmavaram and JA Klein An introduction toassessing process hazards Process Saf Prog 31 (2012)266ndash270
3 EM Davis J Murphy D Silva The CCPS chemicalreactivity evaluation tool Process Saf Prog 31 (2012)203ndash218
4 National Institute for Occupational Health and Safety(NIOSH) Pocket Guide to Chemical Hazards Departmentof Health and Human Services September 2007 Avail-able at wwwcdcgovniosh (accessed February 262013)
5 CHRIS (USCG) ldquoChemical Hazards Response InformationSystem Hazard Chemical Data Manualrdquo CommandmentInstruction Manual M1646512C US Department ofTransportation United States Coast Guard 1999 Avail-able at httpwwwuscgmildirectivescim16000-16999CIM_16465_12Cpdf (accessed March 22 2013)
6 A Streitwieser and C Heathcock Introduction to OrganicChemistry 2nd ed Macmillan New York 1981
7 Parr Instrument Company Instruction Manuals 230MSafety in the Operation of Reactors and Pressure VesselsAvailable at httpwwwparrinstcomsupportdownloadsmanuals230M_Parr_Safety-Lab-Reactorspdf (accessed February 9 2012)
8 Code of Federal Regulations Pipeline and HazardousMaterials Safety Administration (Department of Transpor-tation) 49CFR Parts 171ndash173 (2012)
9 NFPA 45 Fire Protection for Laboratories Using Chemi-cals 2011 edition National Fire Proctection AssociationQuincy 2010
10 AE Theis and CF Askonas Maintain Safety Excellencein Laboratory Facilities AIChE Global Congress on Pro-cess Safety Paper 79a 2012
Process Safety Progress (Vol32 No2) Published on behalf of the AIChE DOI 101002prs June 2013 145
