The Occupational Safety and Health Act of 1970 emphasized the need for standards to protect the health and safety of workers exposed to an ever increasing number of potential hazards in the workplace. Section 22(d)(2) of the Act authorizes the Director of the National In stitu te for Occupational Safety and Health (NIOSH) to make recommendations to the Occupational Safety and Health Administration (OSHA) concerning improved occupational safety and health standards. The purpose of th is document is to provide recommendations for preventing injuries and disease caused by hazardous energy. The document was developed through the use of "systems analysis" so as to provide a logical means of performing maintenance and servicing a c tiv itie s safely, with energy present, with energy removed, and during the process of reenergizing. We gratefully acknowledge the contributions to th is document made by representatives of other Federal agencies or departments, labor unions, trade and professional associations, consultants, and the s ta ff of the In stitu te. Whatever the contributions made by others, conclusions expressed in th is document are those of the In stitu te, and we are so lely responsible for them. However, a ll comments made by those outside NIOSH, whether or not incorporated, were considered carjeiully and were sent with the document to the Occupational Sa^e(ty\ and Health Administration. .A Dona kid M illar, M.D. A ssistant Surgeon General Director, National In stitu te for Occupational Safety and Health The Division of Safety Research, NIOSH, had primary resp on sib ility for devel opment of the recommended guidelines for controlling hazardous energy during maintenance and servicing. Ted A. P ettit served as project o ffic e r and docu ment manager. Boeing Aerospace developed the basic information for considera tion by NIOSH sta ff and consultants under contract No. 210-79-0024.# Figure I. D IA G R A M FOR CO NTRO LLING H A Z A R D O U S ENERGY DU RING M A IN T E N A N C E

# f^> > IM P L E M E N T A T IO N O F S A F E G U A R D S T O C O N T R O L H A Z A R D S WITH E N E R G Y P R E S E N T M A Y BE C H O S E N IN S T E A D O F H A Z A R D O U S E N E R G Y E L IM IN A T IO N B Y D E V IC E S O R T E C H N IQ U E S^ W H E N IT C A N B E D E M O N S T R A T E D T H A T H A Z A R D S A R E C O N T R O L L E D W ITH E N E R G Y P R E S E N T B Y :

# . I D E N T IF Y IN G A L L H A Z A R D O U S E N E R G Y S O U R C E S A N D H A Z A R D O U S R E S ID U A L E N E R G Y , A N D 2 . D O C U M E N T IN G A P R O C E D U R E F O R A N D D E M O N S T R A T IN G T H A T T H E P R O C E D U R E W ILL C O N T R O L H A Z A R D S R E S U L T IN G F R O M E A C H H A Z A R D O U S E N E R G Y ID E N T IF IE D . T H E D E C IS IO N A T T H IS P O IN T IS P R E D E T E R M IN E D B Y T H E O R IG IN A L O P T IO N C H O S E N IN .
I I I I I I

# Legend

# R E C T A N G L E S Y M B O L -I D E N T IF IE S A N E V E N T T H A T R E S U L T S F R O M T H E C O M B IN A T IO N O R E X C L U S IO N O F A C T IV IT IE S O R E V E N T S . A N D G A T E -D E S C R IB E S A N O P E R A T IO N W H E R E B Y C O -E X IS T E N C E O F A L L IN P U T S A R E R E Q U IR E D TO P R O D U C E A N O U T P U T E V E N T S . O R G A T E -D E F I N E S S IT U A T IO N W H E R E B Y A N O U T P U T E V E N T W ILL O C C U R IF O N E O F T H E IN P U T S E X IS T . D E C ISIO N G A T E -E X C L U S IV E O R G A T E W H IC H F U N C T IO N S A S A N O R G A T E B U T P R O V ID E S A F O O T N O T E D ( t > ) L IS T O F D E C IS IO N C R IT E R IA A R E N O T S E L F E V ID E N T . D IA M O N D -D E S C R IB E S A N E V E N T T H A T IS -C O N S ID E R E D B A S IC IN A G IV E N L O G IC S E Q U E N C E . E V E N T IS N O T D E V E L O P E D F U R T H E R B E C A U S E D E V E L O P M E N T IS O B V IO U S .
u n til i t becomes operational. For sim p lification , "maintenance and servicing" are referred to as "maintenance" throughout much of the document.
"Inspection" is defined as checking or testin g machinery, equipment, system, e t c ., against established standards. The d efin itio n suggests that the object being inspected has a function and should comply with a standard. From th is, i t is deduced that (1) a standard must e x ist that: establishes the good or bad ch aracteristics of the object being inspected and (2) the object must be com plete so that i t can perform it s function; i . e . , construction, assembly, or manufacture should be complete before the object can be maintained. I f the object has more than one function, i t may be necessary to change or add parts to the object so that it may perform the d ifferent functions.
The a c tiv ity required to make the changes or additions is considered maintenance. In some sectors of industry the term "set-up" is used to denote the a c tiv itie s needed to change the functions of the equipment.
"Service" is defined as repair or maintenance.
The d efin itio n of service is synonymous with maintenance; however, service (as used in this report) refers to the a c tiv itie s needed to keep a machine, process, or system in a state of efficien cy ; e .g ., changing crank case o i l , greasing, cleaning, painting, adjusting, calibratin g, e tc . Energy. For this document, "energy" means mechanical motion; potential energy due to pressure, gravity, or springs; e le c tr ic a l energy; or thermal energy resulting from higfr or low temperature.
As suggested by one of the approaches taken by industry, maintenance may be performed with power o ff or power on.
Maintenance a c t iv it ie s , however, are always performed with some form of energy on and some form of energy o ff . Thus, the concept of "power off" or "power on" implies that power, the time rate at which work is done or energy emitted or transferred, can be turned o ff. This concept is too r e str ic tiv e because it does not consider gravity or temperature. The term "energy," as opposed to "power," is therefore suggested as an altern ative, because current consensus standards and other litera tu re on th is subject use th is term.
The concept of energy (any quantity with dimensions mass times length squared divided by time squared), however, is too in clu sive.
The concept of energy, for the purpose of th is document, is lim ited to:
1. Kinetic energy -energy possessed by a body by virtue of i t s motion.

# Potential energy -energy possessed by a body by virtue of it s position in
a gravity fie ld .
3. E lectrical energy -energy as a result of a generated e le c tr ic a l power source or a s ta tic source.
Thermal energy -energy as a resu lt of mechanical work, radiation, chemi cal reaction, or e le c tr ic a l resistance.
Radiation, the process by which electromagnetic energy is propagated, is not included because this type of energy a ffects internal organ tolerance, which is a health e ffe c t. Personnel Hazard. A condition which could lead to injury or death. This con d itio n should be recognized by a person fam iliar with the particular circum stances and facts unique to a particular industry. The following concept of personnel hazard was used to objectively identify hazards to humans: A per sonnel hazard e x ists when the environment, conditions, natural phenomena, or equipment ch aracteristics may release le v els of energy that exceed human tolerance.
This concept encompasses the human physiological tolerance to trauma as well as internal organ tolerance to environment. Isolated or Blocked Energy. Energy is considered isolated or blocked when i t s flow would not be reactivated by a foreseeable unplanned event.
The term "isolate" means to set apart from others.
The term "block" (noun) means an obstacle or obstruction; or, (verb) to make unsuitable for passage or progress by obstruction, to prevent normal functioning. These terms are sim ilar in meaning, but they cannot be used synonymously in a ll instances. Although they may describe the same function ( i . e . , prevention of the normal flow of energy), the way in which the function is performed is d ifferen t.
For instance, to control gravitational energy, the energy should be blocked in the sense that an obstacle or obstruction is placed.
It would be incorrect to use the term "isolate" when referring to the control of gravi tation al energy. E lectrical energy should be controlled by iso la tin g it in the sense that i t is set apart, or disconnected. It would be incorrect to use the terra "blocked" when referring to the control of e le c tr ic a l energy.
The terms may be used synonymously in some cases, such as when referring to blocking the passage of fluid or iso la tin g the pressure in a pipe. Sometimes the difference in meaning becomes evident only by the method used to implement the function.

# Point(s)
-f Control. The point or points from which energy-blocking, -is o la tin g , or -d issip atin g devices are controlled.
Securing the Point(s) of Control. The point(s) of control are secured to pre vent unauthorized persons from reactivating the flow of energy. Securing is a separate and d istin ct action from iso la tin g or blocking the energy sources. The use of locks, tags, or posting a qualified person or a combination thereof are methods of accomplishing these c r ite r ia .

# Dissipate Energy.
To cause energy to be spread out or reduced to lev els tolerable by humans.
When the word "dissipate" is applied to the word "energy," the term may be interpreted d iffe r e n tly .
The following concepts should be used to determine the dissipation a c tiv itie s :
1. Dissipate Mechanical Motion -Motion tends to continue because of in ertia after removal of energy; therefore, mechanical motion should be dissipated. For example, a flywheel should be allowed to come to rest before starting work.
Dissipate Potential Energy -Potential energy can be manifested in the form of pressure (above or below atmospheric), springs, and gravity. Gravity can never be eliminated or dissipated; i t can only be controlled. Springs under tension or compression can be released (to d issip ate stored energy) or the stored energy can be controlled.
Pressure may be blocked, iso la te d , or dissipated.
The term "dissipate pressure" implies reducing pressure to a level that would not harm humans.
Normally, th is pressure value is atmos pheric .
Dissipate E lectrica l Energy -D issipation of e le c tr ic ity may be accom plished by "grounding" the d e e lec tr ifie d portion of the c ir c u it after i t has been isolated .
Grounding liv e circ u its may be catastrophic. D issipation of e le c tr ic a l energy includes the actions necessary to prevent the buildup of e le c tr ic a l potential (s ta tic e le c t r ic it y ) .
D issipate Chemicals -Chemical reactions are exothermic or endothermie. Exothermic reactions raise temperatures, which may cause a variety of e ffe c ts such as fir e s , explosions, burns, e tc .
Endothermie reactions lower tempera tures and cause the need for additional heat. Some elements manufactured by endothermie reaction are used as explosives or have explosive ch aracteristics because of their in s ta b ility and rapid release of energy. For the purpose of th is document, emphasis is placed on the e ffo r t necessary for the prevention or control of chemical reactions.
Thus, the term "dissipation of chemicals" implies those actions needed to prevent chemical reactions that would (1) raise or lower temperatures or (2) cause e ffe c ts which humans cannot to lera te.
Dissipate Thermal Energy -Human tolerance to temperature is very lim ited. Human tissu e is harmed when it is exposed to temperatures above 45C (113F) or below 4C (39F). Since temperature cannot be isolated or blocked, the only way to control it s e ffe c ts on humans is through d issip ation or employee protection.
Mechanical motion, e le c tr ic a l resista n ce, chemical reactions, and radiation w ill raise the temperature of materials which, in turn, can burn or damage human tissu e .
Therefore, when energy sources that a ffect temperature are id en tified in equipment, processes, or systems, controls of the energy source should be effected to allow the temperature to dissipate to a tolerable le v e l.

# C. W ORKING WITH OR WITHOUT ENERGY PRESENT
The basic decision that must be made before maintenance begins is: Can the task be accomplished safely with or without energy present or is i t necessary to deenergize before in itia tin g maintenance?

# Concepts which should be considered in th is decision include:
1) Energy is always present; 2) energy is not necessarily dangerous; and 3) danger is present only when energy is released in quantities which exceed human to ler ances. Further, prior to the development of sp ecific energy control measures, a ll energy sources should be:
1) id en tified ; 2) analyzed independently; and 3) analyzed in combination with any other energy sources present.
The following paragraphs present c r ite r ia which should be considered during analysis of sp ecific energy sources.
-5 -D.

# ENERGY SOURCES
Mechanical motion can be linear translation or rotation, or i t can produce work which, in turn, produces changes in temperature. This type of energy can be turned o ff or le f t on.
P otential energy can be due to pressure (above or below atmospheric), springs, or gravity.
Maintenance is always conducted with gravity on. Potential energy manifested as pressures or in springs can be dissipated or controlled; i t cannot be turned o ff or on. E lectrical energy refers to generated e le c tr ic a l power or s ta tic e le c t r ic it y . In the case of generated e le c t r ic it y , the e le c tr ic a l power can be turned on or turned o ff .
Static e le c tr ic ity may not be turned off; i t can only be d is s i pated .
Thermal energy is manifested by high or low temperature. This type of energy is the result of mechanical work, radiation, chemical reaction, or e le c tr ic a l resistance.
It cannot be turned o ff or eliminated; however, it can be d is s i pated or controlled.

# Chemical reaction is manifested by exothermic or endothermic e ffe c ts .
In either case, the energy-on/energy-off approach does not apply.
Any material which could chemically react should be eliminated, dissipated, or controlled. That i s , some p ositive measures must be taken to (1) eliminate the chemical so that no chemical reaction can take place, or (2) control the reaction so that the energy released by the chemical reaction w ill not harm humans. Methods of controlling hazards due to chemicals or chemical reactions as energy sources have not been addressed in th is document because of their complexity. These c riter ia indicate that some energy sources can be turned o ff , some can be dissipated, other sources of energy can be eliminated, and some can only be controlled. The following examples illu s tr a te how th is concept is applied.

# Example 1:
The task is the removal and replacement of a spring in a car. Potential energy is present due to the force of gravity and of the tension or compres sion of the spring. The force of gravity can be controlled only by blocking the car. The energy stored in the spring can be dissipated or controlled. It is usually controlled by blocking the release of the spring.
Therefore, the decision logic indicates that maintenance must be done with energy present.

# Example 2:
A large mixing drum with internal rotating blades is in need of repair. One of the mixing blades is out of alignment.
The established maintenance pro cedure requires the entry of two men to realign the blade.
The e le c tr ic a l energy source can be switched o ff and locked out and/or the mechanical lin k ages can be disconnected. The lockout at the switch w ill provide a physical barrier and a tag w ill identify the task being performed. In addition, i f the mechanical linkages are disconnected, a ll energy sources, except gravity, w ill be removed from the system.
-6 -I I .

# INVESTIGATION OF THE PROBLEM
Much of the data examined during th is study did not include enough sp e cific information to id en tify the factors causing or contributing to accidents which occur during maintenance as a result of inadequate energy control measures.
However, an extensive search of world litera tu re related to maintenance haz ards and maintenance hazard controls, revealed a number of accident scenarios which could be evaluated in the attempt to id en tify generic causes of maintenance-related accidents.
Accidents which could be attributed to the presence of uncontrolled energy during maintenance a c t iv it ie s were selected for closer study. Although the limited nature of the information precluded exact cause determination, the scenarios did provide a general indication of causes or contributing causes as well as illu str a tio n s of the types of a c ci dents that can occur when hazardous lev els of energy are not controlled.

# A. THE ACCIDENT SCENARIOS
Out of 300 accident scenarios found in 14 d ifferen t sources, 59 accidents were selected to illu s tr a te that adequate energy control methods may have prevented the accidents.
(A b rief description of each accident is included in Appendix B.) Causes of these accidents have been categorized as follows:
1. Maintenance a c tiv itie s were in itia te d without attempting to deenergize the equipment or system, or control the hazards with energy present.
Twenty-seven accidents f e l l into th is category. Typical of these accidents was accident No. 10 (Appendix B), in which an experienced repairman saw a piece of wire stuck in a f i l t e r wheel. He attempted to remove the wire while the wheel was in motion. Losing his balance, he f e ll into the wheel. His leg was crushed and had to be amputated.

# Energy blockage or iso la tio n was attempted, but was inadequate.
Six incidents were the result of in e ffec tiv e energy iso la tio n or blockage.
An example was accident No. 30 (Appendix B), in which a worker attempted to prevent an elevator from moving by jamming the doors open with a plank while the elevator was on the second floor, and then turning o ff the outside panel switch on the main floo r. He was k ille d while working on the main floor when the elevator returned to i t s home base rather than remaining on the second floor.

# Residual (potential) energy was not dissipated.
Accident No. 34 (Appendix B) resulted in injury due to failure to dissipate residual energy.
The worker turned o ff the power to a packaging machine and attempted to remove a jam. Residual hydraulic pressure activated the holding device causing the injury.

# Accidental activation of energy.
Twenty-five of the accidents were caused by accidental a ctivation . These accidents were caused by either (1) persons unintentionally actuating controls, or (2) by other persons activating the controls, not realizin g that maintenance was in progress. The r esu lt, in either case, can be disastrous.

# An accident typical of th is category was accident No. 36 (Appendix B) in which a mechanic was repairing an e le c tr ic a lly operated caustic pump.
A co-worker dragged a cable across the toggle switch that operated the pump, and the mechanic was sprayed with ca u stic. Another incident, accident No. 38 (Appendix B), occurred when an employee was cutting a pipe with a torch and d iesel fuel was mistakenly discharged into the lin e . The ensuing ignition of the d iesel fuel resulted in a f a ta lity . These types of accidents are preventable i f e ffe c tiv e energy control tech niques or procedures are availab le, workers are trained to use them, and management provides the motivation to ensure their use.
Table I summarizes the accident causes and indicates the applicable guidelines from Chapter III which, i f followed, would have eliminated the hazard and prevented the a c ci dent. In Appendix B, an energy control method that would have been e ffe c tiv e is id en tified for each entry. The methods shown are only examples. For many cases, several energy control techniques could have been used to prevent the accident.
In addition, Appendix B id e n tifie s the hazard types, energy sources, and accident causes as w ell as consequences of each accident.

# STATISTICAL INVESTIGATION
Besides the literatu re search, a s t a t is t ic a l investigation was undertaken in the attempt to obtain data that would help to identify factors causing or contributing to the type of accident under consideration.
It was planned that s t a t is t ic a l accident data would be obtained that related to inadequate energy controls during maintenance. The data would help to id en tify in e ffec tiv e control methods and particular problems that should be avoided. Manual and automated searches were conducted to locate the informa tion .
Most of the data found, however, did not include enough sp ecific information to identify the factors causing or contributing to the accidents. This Existing data are very lim ited .
Occupational injury data are often gathered primarily for the purpose of processing worker's compensation claims rather than for developing countermeasures.
Most current information systems emphasize data about the injury, not the accident, and about the end resu lts of the accident sequence, rather than the precipitating events and conditions leading to the injuring event. Data of the la tter type are often much more important for the development of countermeasures.

# Ihe ANSI Z16.2 American National Standard Method of Recording Basic Facts
Relating to the Nature and Occurrence of Work Injuries, or an adaptation of this coding method, is used almost exclu sively among both the Federal and State Government agencies and private sector information systems. The ANSI Z16.2 method is extremely lim ited and is designed primarily as a monitoring tool for grouping accidents by major types and for flagging a lim ited number of isolated factors about accidents so that the cases can be recalled when data analysis begins.
The ANSI Z16.2 method is not designed as an analytical tool for identifying the patterns, the precipi tating events and conditions in an accident sequence, or the relationships among contributing causal factors in an accident that are normally needed for countermeasure development."
Attempts to obtain more sp e cific data from such sources as association s, insurance companies, labor unions, and industry proved unsuccessful because of one or more of the following reasons:

# Energy i s c o n sid e r e d a d e q u a te ly i s o l a t e d , b lo c k e d , o r d is s ip a t e d when an unplanned e v e n t would n o t r e a c t i v a t e th e flo w o f e n e r g y .
Adequate iso la tio n can be achieved by many methods or combinations of methods so long as the controls are not lik e ly to be accidentally turned on.
Appendix A id e n tifie s several examples of methods of e ffe c tiv e ly iso la tin g or blocking energy.

# b . S to r e d o r r e s id u a l energy th a t c o n s t i t u t e s a p e rso n n e l h azard s h a ll be i s o l a t e d , b lo c k e d , o r d is s ip a t e d .
Another necessary step is to block or d issip a te any hazardous residual energy once the decision is made to deenergize. Residual energy is not always as obvious a hazard as the incoming energy supplies.
For th is reason, special effo rt must be made to id en tify any stored energy that could result in personnel hazards.
For example, i f i t is necessary fo r a worker to climb or move about m echanical lin k a g e s, the p o t e n t i a l energy due to the w o rk e r's weight may be s u f f i c i e n t to cause dangerous movements o f the lin k a g e s. I f t h i s hazard is p re s e n t, a m echanical block or pin can u s u a lly be used to block out the energy and p o t e n t i a l l y dangerous movement.
Forms o f p o t e n t i a l energy which may be s to re d in s u f f i c i e n t q u a n t i t ie s to re p re se n t h azard s in clude:

# c . The p o i n t ( s ) o f c o n t r o l s h a l l h e s e c u r e d s o t h a t u n a u t h o r iz e d p e r s o n s a r e p re v e n t e d from r e e n e r g i z i n g th e m a c h in e , p r o c e s s , o r s y s t e m .

# A m eans o f s e c u r i t y m ust b e im plem ented t o e n s u r e t h a t th e equipm ent b e in g m a in t a in e d o r s e r v i c e d i s n o t somehow r e e n e r g iz e d . The g u id e l i n e s a llo t r a c h o ic e o f t h r e e m eth o d s.
The s e le c tio n should be based on the p a r t i c u l a r circum stances and c h a r a c t e r i s t i c s of each re s p e c tiv e f a c i l i t y or a p p lic a tio n .
A farm employee working with p o t e n t i a l l y hazardous powered equipment in a remote f i e l d would not be expected to use a padlock for s e c u r ity .
A padlock (or e q u iv a le n t) , however, would be a lo g ic a l s e le c tio n for a sw itch or v alve a c c e s s ib le to a larg e number of people.
The use of tag s, when only tra in e d p er sonnel have access to the p o in t( s ) of c o n tro l is an accepted in d u stry p r a c tic e .
Any one o f the follow ing methods w ill prevent unwanted re e n e r g iz a tio n of equipm ent.

# t " ) su c h t h a t r e e n e r g i z i n g th e sy ste m r e q u i r e s th e u s e o f s p e c i a l equipm ent r o u t i n e l y a v a i l a b l e o n l y t o th e p e r s o n who a p p li e d th e c o n t r o l . A w a rn in g c o n t a i n i n g a p p r o p r ia t e in f o r m a t io n s h a l l be d i s p l a y e d a t th e p o i n t ( s ) o f c o n t r o l .
The method of securing the p o in ts of c o n tro l by physical means th a t prevent unauthorised persons from re e n e rg iz in g the machine, p ro cess, or system is w idely used.
The most common device used fo r s e c u r ity is the padlock. Often each worker is provided w ith h i s own padlock and the only key.

# c k e d , o r d i s s i p a t e d , th e d a t e , th e p e r s o n ( s ) r e s p o n s i b l e f o r th e c o n t r o l m e a su re , and th e p e r s o n ( s ) r e s p o n s i b l e f o r th e w ork t o b e a c c o m p lis h e d . i n a d d i t i o n , a c c e s s t o th e c o n t r o l p o i n t ( s ) o u s t be l i m i t e d t o p e r s o n s who a r e t r a in e d t o u n d e r s ta n d and o b s e r v e th e p o s t e d w a r n in g .
Access may be lim ite d by physical lo c a tio n (such as e le v a tio n ) or by procedural means such as color-coded badges.
When th is method of s e c u r ity is used , each new employee should re c e iv e tr a in in g to observe the g u id e lin e s b efo re having access to the p o in t(s ) used for c o n tr o llin g energy. The tra in in g should in clude the purpose of the w arning, the format and co lo r of the w arning, and should s t r e s s the r e s p o n s i b i l i t y of each person fo r h i s co-w orkers' s a f e ty . R etrain in g should be given as necessary so th a t the im portance of observing the posted warning is no t fo r g o tte n .

# ( 3 ) P o s t q u a l i f i e d p e r s o n n e l , w ith th e s p e c i f i c r e s p o n s i b i l i t y o f p r o t e c t i n g a g a i n s t u n a u t h o r iz e d a c t u a t i o n , a t th e p o i n t ( s ) o f c o n t r o l t h ro u g h o u t th e m a in te n a n ce a c t i v i t y . T h is a p p l i e s m a in ly t o s h o r t d u r a t io n w ork i n th e im m ediate v i c i n i t y o f th e c o n t r o l p o i n t ( s ) . d . B e f o r e s t a r t i n g m a in te n a n c e , v e r i f y t h a t s t e p s a . th ro u g h c . h a v e been e f f e c t i v e i n i s o l a t i n g , b l o c k i n g o r d i s s i p a t i n g h a z a r d o u s e n e r g y , and s e c u r i n g th e p o i n t ( s ) o f c o n t r o l .
In applying any method or technique to i s o l a t e , b lo ck , or d i s s ip a t e energy from s p e c if ie d a re a s, d evices, machines, system s, or p ro c esses, i t should be v e r i f i e d th a t d e e n e rg iz a tio n has been e ffe c te d p rio r to the s t a r t of m aintenance. V e r if ic a tio n should be accomplished each time energy is elim in a te d and re a p p lie d , re g a rd le s s of the time i n t e r v a l between removal and r e a p p lic a tio n .
Proven methods should be used to e f f e c ti v e l y dem onstrate th a t a l l hazardous energy has been i s o l a te d , blocked, or d is s ip a te d in the areas where personnel w ill perform the req u ired ta s k s .
I f th ere is the p o s s i b i l i t y of reaccum ulation of energy to hazardous le v e ls , v e r i f i c a t i o n should be continued u n t i l the m aintenance a c t i v i t y is com pleted. The devices should be re g u la r ly and fre q u e n tly in sp ected and/or c a li b r a te d to ensure th a t they are fu n c tio n a l and a c c u ra te and to d e te c t any p o t e n t i a l device f a i l u r e s .
Good in te n tio n s to e lim in a te energy have f a il e d and i n j u r i e s have re s u lte d when the wrong sources of energy were c o n tro lle d .
To avoid t h i s p o s s i b i l i t y , the energy should be v e r i f i e d to be below hazardous le v e ls b efo re proceeding. This a c tio n is so obvious th a t many re fe re n c e s f a i l to i d e n tif y i t ; y et i t is v i t a l l y im portant th a t i t be included in each procedure. The procedures should c l e a r l y a ssig n r e s p o n s i b i l i t y for each ste p of the c r i t e r i a as w e ll as in d ic a te where i s o l a t i o n , b lo ck in g , or d i s s ip a t io n of energy is to be accom plished, how d e e n e rg iz a tio n is to be v e r i f i e d , what method is to be used fo r s e c u r i ty , and how r e s p o n s i b i l i t y is to be tr a n s f e r r e d during s h i f t changes.

# . F o r t h e f i v e s t e p s l i s t e d a b o ve t o c o m p r is e a v a l i d t e c h n iq u e f o r c o n t r o l l i n g h a z a r d o u s e n e r g y s o u r c e s , th e f o l l o w i n g two p r e c o n d i t i o n s m ust
The procedures need not be unique for a s in g le machine or ta sk ; procedures may be used which apply to a group o f s im ila r machines or ta s k s .
Depending upon the com plexity of the equipment and i t s a p p lic a tio n , good procedures may vary from one to many pages.
No m a tte r how simple and s tra ig h tfo rw a rd the procedures may seem, they should be documented so th a t a l l le v e ls of personnel understand company p o lic y , as w ell as the re q u ire d s a f e ty procedures.

# b . The p e r s o n n e l who im plem ent th e a b o ve s t e p s s h a l l be q u a l i f i e d . E a ch w o rk e r m ust t h o r o u g h ly u n d e r sta n d a l l docum ented p r o c e d u r e s . T r a i n i n g s h a l l b e a c c o m p lis h e d a s n ec essary t o e s t a b l i s h and m a in t a in p r o f i c i e n c y , and t o e n com p a ss p r o c e d u r a l o r eq u ip m ent c h a n g e s w h ich a f f e c t e n e r g y c o n t r o l d u r i n g m a in te n a n ce .
A fte r the energy c o n tro l need has been i d e n t i f i e d , the methods o f im plem entation s e le c te d , and the procedures f in a l iz e d , a t r a in in g program should be i n s t i t u t e d to ensure th a t the procedures are followed and the purpose and fu n ctio n s are understood.
The t r a in in g should involve elem ents of management and the w orkforce concerned w ith m aintenance a c t i v i t i e s so th a t the c r i t e r i a are e x p e d itio u s ly and u n i formly a p p lie d .
The tr a in in g should ensure th a t the u n d erstan d in g and s k i l l s re q u ired fo r the safe a p p lic a tio n and removal of energy con t r o l s are a v a ila b le as re q u ire d .
R etrain in g should be scheduled as -1 4 -
C l i X U L i 11 J .
- fte n as n ec essary to m ain tain p ro fic ie n c y and to in tro d u ce re v ise d dev ices, p r a c t i c e s , and methods.
I f energy i s o l a t i o n , b lo ck in g , or d i s s ip a t io n are secured accord in g to c r i t e r i o n 2 . c . ( 2 ) , then every person having job r e la t e d access to the p o in t( s ) of c o n tro l should be tra in e d . This tr a in in g is in a d d itio n to th a t re q u ired fo r personnel involved in applying energy c o n tro ls . The t r a in in g should in clude the purpose of the w arning, the format and c o lo r of the w arning, and should emphasize the extreme im portance for a l l personnel to obey the warnings in ord er to p ro te c t t h e i r co w orkers.
The personnel who implement the procedures should be tra in e d not only to know how to accom plish the ste p s re q u ired to c o n tro l energy so u rces, but a ls o to understand the hazards a s s o c ia te d w ith energy so u rc es.
All le v e ls of su p e rv is io n concerned w ith m aintenance and s e r v ic in g , w ith s p e c ia l emphasis on f i r s t -l i n e su p e rv isio n , must be tra in e d in o rd e r to ensure th a t procedures are follow ed.

# B . CONTROLLING HAZARDS WITH ENERGY PRESENT C o n t r o l l i n g m a in te n a n ce h a z a r d s w ith e n e rg y p r e s e n t i s th e o n l y a l t e r n a t i v e t o d e e n e r g i z in g t o p e rfo rm m a in te n a n ce t a s k s s a f e l y . F o r some t y p e s o f m a c h in e s o r p r o c e s s e s , th e c o n d i t i o n s o r c o m b in a t io n o f c o n d i t i o n s t h a t m ust be e v a l u a t e d a n d c o n t r o l l e d i n e n e r g iz e d s y s t e m s ca n be much more com p lex th a n d e e n e r g i z e d s y s t e m s . The f o l l o w i n g p a r a g r a p h s d e s c r i b e g u i d e l i n e s f o r m a in t a in i n g " e n e r g i z e d " s y s t e m s .

# . H a z a rd o u s e n e r g y s o u r c e s , i n c l u d i n g r e s i d u a l e n e rg y s o u r c e s , s h a l l b e i d e n t i f i e d .
I d e n t i f i c a t i o n of the hazards needs no j u s t i f i c a t i o n , fo r a hazard cannot be c o n tro lle d u n less i t is i d e n t i f i e d .

# . Docum ented p r o c e d u r e s , w h ich h a v e b een d e te rm in e d t o c o n t r o l each h a z a r d o u s e n e r g y s o u r c e , s h a l l b e u s e d . P r o c e d u r e s s h a l l a s s i g n r e s p o n s i b i l i t y and a c c o u n t a b i l i t y f o r c o n t r o l l i n g p e r s o n n e l h a z a r d s .
Before a worker is exposed to a h az a rd , the hazard c o n tro ls must be known to be e f f e c t i v e . D eterm ination of hazard c o n tro l e f fe c tiv e n e s s can be based on p hysical dem onstration p rio r to im plem entation on a d ay -to-day b a s is . This can be by s i m i l a r i t y to a dem onstrably e f f e c t i v e hazard c o n tr o l, or by a n a ly s is .

# . P e r s o n n e l who p e rfo rm t h e m a in te n a n ce s h a l l be q u a l i f i e d t o u se th e p r o c e d u r e s . Q u a l i f i c a t i o n t o u se th e p r o c e d u r e s may b e o b t a in e d b y e d u c a t io n , e x p e r ie n c e a n d / o r t r a i n i n g .
The personnel who perform the m aintenance and s e r v ic in g a c t i v i t i e s must be tra in e d to understand the p a r t i c u l a r h azard s, the c o n tro ls for the h az ard s, and how to implement the c o n tro ls e f f e c t i v e l y .

# IV. CONCLUSIONS
This study confirms th a t the need to c o n tro l hazardous energy during m ain te nance a c t i v i t i e s is recognized by in d u s try , lab o r, and the Government. This need is m anifested by the d i f f e r e n t approaches implemented by in d u stry to reduce i n j u r i e s , the evidence subm itted to the O ccupational S afety and Health A d m in istration a t p u b lic h ea rin g s on the s u b je c t of lockouts and ta g o u ts , and r e s u l t s of the l i t e r a t u r e search in which a g re a t number of a r t i c l e s were found which emphasize the need fo r some type o f c o n tro l.
The l i t e r a t u r e review did not produce s t a t i s t i c a l evidence of the e f f e c t i v e ness o f any one s p e c if ic type o f energy c o n tro l method over an o th e r, nor did i t id e n tify ac cid en t c a u sa tiv e fa c to rs leading to i n j u r i e s .
No values could be developed which d i f f e r e n t i a t e ac c id e n ts and i n j u r i e s o ccu rrin g during main tenance from aggregate U.S. in ju ry s t a t i s t i c s ; i . e . , d ata to provide in d ic e s on the p ro b a b ility o f in ju ry occurrence, the magnitude o f the i n j u r i e s , and the exposure to the hazard (p o pulation of workers a t r i s k ) th a t c o r r e l a t e with the i d e n t i f i e d primary hazard causes.
I n d u s t r i a l accid en t and in ju ry d ata a v a ila b le in the U.S. d e sc rib e the in ju r i e s s u s ta in e d by the workers in g re a te r d e t a i l than the causes of the a c c i d en ts th a t i n f l i c t e d the i n j u r i e s .
The hazard causes found in the analyzed ac cid en t re p o rts are c a te g o riz e d by f i r e , ex p lo sio n , im pact, f a l l , caught in or between, and o th e rs .
The hazard causes id e n t i f i e d by t h i s study are d i f f e r e n t .
Consequently, the published s t a t i s t i c s (aggregates of a c c id e n t/in ju r y re p o rts ) cannot be broken down in to ac cid en t causes id e n t i f i e d as s p e c if ic to m aintenance and s e r v ic in g a c t i v i t i e s .
The study i d e n t i f i e d the follow ing hazard causes:
Maintenance a c t i v i t i e s were i n i t i a t e d w ithout a ttem p tin g to deen erg ize the equipment or system or c o n tro l the hazard with energy p re s e n t.
Energy blockage or i s o l a t i o n was attem p ted , but was in adequate.
3. R esidual energy was not d is s ip a te d .
Energy was a c c id e n ta lly a c tiv a te d .
The worker p opulation a t r i s k could not be d efined because employers who implement procedural c o n tro ls may choose to make the procedures a p p lic a b le to (1) a l l personnel;
(2) personnel engaged in any one or any com bination o f a c t i v i t i e s such as c o n s tru c tio n , o p e ra tio n s , m anufacturing, te s t i n g , e t c . ; or (3) m aintenance personnel only.
Thus, the e f fe c tiv e n e s s of any one method of c o n tro l w ith re s p e c t to an o th er cannot be determ ined.
However, the implemen ta t i o n o f any method which in c re a se s worker awareness of p o t e n t ia l l y hazardous energy sources is b e t t e r than no method a t a l l . Most of these e x is tin g re g u la tio n s use the concept of "power o ff" to prevent i n j u r i e s , and do not -1 6 -pro v id e guidance on how to d is c e rn when to apply lo ck s, ta g s , or a com bination o f locks and ta g s .
They a ls o do not allow fo r the perform ance of m aintenance w ith power on, even under norm al, everyday c o n d itio n s , or when such m ain te nance cannot be performed w ith power o f f . In f a c t , p e r sonnel can be harmed by to x ic , c a u s tic , or asphyxiant m a te r ia ls with no con c u rre n t r e le a s e of energy.
I t is th e re fo re recommended th a t c r i t e r i a be developed s p e c i f i c a l l y to p ro te c t m aintenance personnel from such hazardous m a te r ia ls . The re searc h e f f o r t should focus on id e n tify in g p o t e n t i a l h az a rd s and determ ining c o r r e c tiv e a c tio n which e i t h e r reduces hazardous energy le v e ls or changes the w o rk e r's proxim ity to hazardous energy.
-1 9 -V I. REFERENCES 1. M anufacturing Chemists A sso cia tio n .
Case H is to rie s of A ccidents in the Chemical In d u stry .
Washington, DC: 1962DC: -1975. 5 v o l.
2. G lasser, Melvin A. Data Regarding O ccupational F a t a l i t i e s Concerned With Safety Lockout.
In te r n a tio n a l Union, UAW, D e tr o it, MI: June 29, 1979. 3pp.
3. American Petroleum I n s t i t u t e .
Review of F a ta l I n ju r i e s in the Petroleum In d u stry fo r 1978.
Washington  -3 1 -

# 2] AN EM PLOYEE ATTEM PTED TO R EM O V E SO M E CLOGGED CO M PO ST M ATERIAL THAT HAD JAM M ED AN OPERATING KILN DISCHARGE CONVEYOR. HIS CLOTHING BECAM E ENTANGLED IN THE UNGUARDED REVOLVING ROLLERS. HIS ARM W A S CAUGHT IN THE M ACHINE. H E W A S PULLED AGAINST TH E M ACHINE AND W A S CH OK ED TO DEATH.

# 22^ n n

# AN EM PLOYEE W A S ATTEMPTING TO CLEAR A JAM ON A GARNETT M A CHINE W HILE IT W A S IN OPERATION. HE CRAW LED INSIDE THE M ACHINE TH RO UG H AN UNGUARDED H O LE W H ER E HE BECAM E ENTANGLED IN M OVING PARTS, W A S DRA W N INTO THE ROLLER AND W A S CRUSHED.

# T T .
[Ti LACERATIONS 1       The e x is tin g B r itis h Code of P ra c tic e r e l i e s on th e human element to follow a documented "perm it to work" system for perform ing m aintenance. I t c lo s e ly p a r a l l e l s the recommended g u id e lin e s , and r e l i e s on the documented system to serv e as a record o f a l l the fo re se e a b le hazards which have been considered in advance.

# ROTATION ELECTRICAL AN EM PLOYEE W A S CLEANING AN EDGER DISCONNECT SA W IN A SAW M ILL. PROTECTIVE FATALITY PANELS W ER E REM OVED. HE REQUESTED ANOTHER EM PLOYEE TO START THE SAW . HIS CLOTHES BECAM E ENTANGLED AND HE W A S PULLED INTO THE SAW .

# 24^  CRUSHED I ROTATION ELECTRICAL AN EM PLOYEE W A S EM PTYING DO UG H DISCONNECT FRO M A M IXER W HILE IT W A S STILL FATALITY RUNNING. W H EN H E REACHED INTO THE M ACHINE HIS ARM W A S CAUGHT AND H E W A S PULLED INTO THE M ACHINE.
I t a lso r e l i e s h e a v ily on s u p e rv isio n to see t h a t the system oper a te s p ro p erly .
The Consensus Standards are s im ila r to the recommended g u id e lin e s .
They pro v id e the o p tio n s of (1) sec u rin g the p o in t( s ) o f c o n tro l by lockout or tag o u t dev ices or (2) having no locks or ta g s, provided o th e r requirem ents are met. These s ta n d a rd s, however, do not allow the o p tio n of having a person remain a t th e p o in t(s ) of c o n tro l to p ro te c t a g a in st u n authorized a c tu a tio n of the ma chine or process during m aintenance and s e r v ic in g .
Also, the stan d ard s do not cover the broad spectrum o f h azard s as do the recommended g u id e lin e s .

# N ational Standards
The e x is tin g n a tio n a l stan d ard s as shown in Table C-4 are not uniform in t h e i r coverage.
In c o n sis te n c ie s in the requirem ents e x i s t between i n d u s tr ie s and between equipment w ith in the same in d u s try .
Some s e c tio n s of the General In d u stry Standards imply lo ck in g out or tagging out energy r a th e r than s p e c i fying th a t lockouts or ta g o u ts be perform ed.
S ections of the standard cover ing in d u s tr ie s or equipment re q u irin g p ro v isio n s fo r only locking out or ta g ging out energy are: overhead and gantry cran es; woodworking m achinery; m echanical power p re sse s ; c e r t a i n fo rg in g m achines; c e r t a i n pulp, paper, and paperboard m ills ; t e x t i l e s ; c e r t a i n bakery equipment; and c e r t a i n sawmill equipment.
Other

# S ta te Standards
The e x is tin g s t a t e stan d ard s (Table C -5 261 (e (1 2 )( i i i ) 1 4 5 (f)( 3 ) ( i i i )
261 (e (13) 1 179(g)( 5) (i) 261 (f ( 6 ) (i) '
17 9 (g )( 5) ( i i ) 261 (g (4) ( i i ) < 1 7 9 ( g ) ( 5) ( iii)   to prevent unauthorized persons from reenergizing the system; using warning tags to caution personnel that energy has been isolated and the reason for isolation; verifying that isolation of energy has been effective; verifying that personnel have cleared the area prior to reenergizing the machine or system; documenting procedures; and ensuring that personnel who implement the criteria have been adequately trained to thoroughly understand the procedures.
261 (g (1 5 )(i) < 179(1) (2) Ci) (c) 261 (g (1 6 )(i) i 1 8 1 (f)( 2 ) ( i ) ( c ) 261 (g (1 9 )( i i i )  2 1 3 (a )(10) 261 (g (21) ' ' 213(b)(5) 261 (j ( 1 ) ( i i i ) i 2 1 7 (b )( 8 ) (i) 261 (j ( 4 ) ( i i i ) t 217( d ) ( 9 ) (iv) 261 (j ( 5 ) ( i i i ) E 218( a ) ( 3 ) ( i i i ) 261 ( j (6) (i) I 2 1 8 (a )( 3 ) (iv) 261 (k ( 2 ) ( i i ) c 218(d) (2) 262(c (1) c 218(e)(1) ( i i ) 262 (n (2) 3 2 18(f)(1) 262(p (1) 3 2 18(f)(2) 262 (q (2) 3 218(g)(1) 263(k (1 2 )(i) 3 218(h)(2) 263(1 ( 3 ) ( i i i ) ( b ) 3 218(h)(5) 263(1 ( 8 ) ( i i i ) i 218( i ) (1) 265 (c (1 2 )(v
The Michigan standards closely parallel the recommended guidelines except Michigan does not include verification that blocking, isolating, and dissipa ting hazardous energy have been effected before starting maintenance.

# International Standards
International standards from Canada, Germany, and Britain (summarized in Table C-6) parallel portions of the recommended criteria. The Alberta, Canada, regulations for machinery and equipment state that no maintenance or repairs shall be carried out until the machinery or equipment has been shut down and secured against accidental movement or the power control devices have been locked out in an inoperative mode by the installation of lockout devices and warning tags.
Dissipation of stored energy, verification that isolation and dissipation have been effected prior to starting maintenance, and verification that upon completion of maintenance, personnel are clear of the danger points before the machine or equipment is reenergized are also included as require ments.
The German specifications for setup, troubleshooting, and maintenance of power-driven equipment state that these tasks must only be performed when:
(1) The hazardous movements are brought to a halt; (2) the initiation of haz ardous movements as a consequence of stored power or energy is prevented; and
(3) unauthorized, erroneous, or unexpected initiation of hazardous movements is avoided by some adequate means.
The British Code of Practice for Safeguarding of Machinery states that effec tive control of hazards during maintenance can be achieved by having a written "permit to work" system. Such a system must clearly identify the hazards and document the practices to be followed, precautions to be taken, and responsi b ilitie s of the workers and of management. The code of practice also calls for adequate training of workers and supervision in safe systems of work and lockout systems for maintenance operation.

# Consensus Standards
The ANSI and NFPA standards (Table C-7) establish requirements and procedures for lockout/tagout of energy sources for stationary machines and equipment and for electrical circuits and electrical equipment, respectively.
These stan dards require (1) that energy sources be isolated or blocked for maintenance, (2) that stored energy be dissipated prior to beginning maintenance, (3) that physical means or devices be used to secure the energy sources, (4) verifica tion that the energy sources have been isolated prior to starting work, (5) verification that all personnel are clear of hazards before reenergizing the machines or systems, (6) assurance that the procedures for lockout/tagout have been documented, and (7) that personnel have been adequately trained to under stand and implement the recommended guidelines.
Applicability of the ANSI standard is limited to unexpected energization, startup, or release of stored energy of equipment or process.
The NFPA standard does not have such a limitation but covers only electrical energy. The recommended guidelines are applicable for all phases of maintenance and servicing.
-5 2 -   This valve shall be closed and locked in the off position while the hammer is being adjusted, repaired, or serviced, or when the dies are being changed.
(ii) A ir-lift hammers shall have an air shutoff valve as required in paragraph (d)(2) of this section and should be conveniently located and distinctly marked for ease of identification.
( iii) A ir-lift hammers shall be provided with two drain cocks: one on main head cylinder, and one on clamp cylinder.
(1) Mechanical forging presses.
When dies are being changed or maintenance is being performed on the press, the following shall be accomplished:
(1) The power to the press shall be locked out.
(ii) The flywheel shall be at rest.

# 1910.252(c)(2)
1 9 1 0 .2 1 8 (g ) (i) The hydraulic pumps and power apparatus shall be locked out.
(ii) The ram shall be blocked with a material the strength of which shall meet or exceed the specifica tions or dimensions shown in Table 0-11. (1) Hot trimming presses.
The requirements of para graph (f)(1) of this section shall also apply to hot trimming presses.
(2) Lockout. Upsetters shall be provided with a means for locking out the power at its entry point to the machine and rendering its cycling controls inoperable.
(5) Changing dies.
W hen dies are being changed, main tenance performed, or any work done on the machine, the power to the upsetter shall be locked out, and the fly wheel shall be at rest.
(1) Boltheading.
The provisions of paragraph (h) of this section shall apply to boltheading.
(2) Rivet making.
The provisions of paragraph (h) of this section shall apply to rivet making.
(1) Billet shears.
A positive-type lockout device for disconnecting the power to the shear shall be provided.

# AND BRAZING (i) Installation.
All equipment shall be installed by a qualified electrician in conformance with subpart S of this part. There shall be a safety-type disconnect ing switch or a circuit breaker or circuit interrupter to open each power circuit to the machine, conveniently located at or near the machine, so that the power can be shut off when the machine or its controls are to be serviced.
(ii) Capacitor welding.
Stored energy or capacitor discharge type of resistance welding equipment and control panels involving high voltage (over 550 volts) shall be suitably insulated and protected by complete enclosures, all doors of which shall be provided with suitable interlocks and contacts wired into the control circuit (similar to elevator interlocks).
Such inter locks or contacts shall be so designed as to effective ly interrupt power and short circuit a ll capacitors when the door or panel is open.
A manually operated switch or suitable positive device shall be installed, in addition to the mechanical interlocks or contacts, as an added safety measure assuring absolute discharge of all capacitors.
(a) The controller disconnecting means is capable of being locked in the open position.

# GENERAL SAFETY AND HEALTH PROVISIONS

# 1926.20(b)
(3) The use of any machinery, tool, material or equip ment which is not in compliance with any applicable requirement of this part is prohibited. Such machine, tool, material, or equipment shall either be identified as unsafe by tagging or locking the controls to render them inoperable or shall be physically removed from its place of operation.

# NONIONIZING RADIATION
(e) Beam shutters or caps shall be utilized, or the laser turned off, when laser transmission is not actually required. When the laser is left unattended for a substantial period of time, such as during lunch hour, overnight, or at change of shifts, the laser shall be turned off.

# FIRE PROTECTION AND PREVENTION

# 1926.150(d)(1)
(ii) During demolition or alterations, existing auto matic sprinkler installations shall be retained in service as long as reasonable.
The operation of sprinkler control valves shall be permitted only by properly authorized persons. Modification of sprinkler systems to permit alterations or additional demolition should be expedited so that the automatic protection may be returned to service as quickly as possible. Sprinkler control valves shall be checked daily at close of work to ascertain that the protection is in service.

# 1926.200(h)
(1) Accident prevention tags shall be used as a temporary means of warning employees of an existing hazard, such as defective tools, equipment, etc. They shall not be used in place of, or as a substitute for, accident prevention signs.
(2) Specifications for accident prevention tags similar to those in Table G-l shall apply.
(a) All fixed power driven woodworking tools shall be provided with a disconnect switch that can either be locked or tagged in the off position.

# W ELDING AND CUTTING
(g) For the elimination of possible fire in enclosed spaces as a result of gas escaping through leaking or improperly closed torch valves, the gas supply to the torch shall be positively shut off at some point out side the enclosed space whenever the torch is not to be used or whenever the torch is left unattended for a substantial period of time, such as during the lunch period.
Overnight and at the change of shifts, the torch and hose shall be removed from the confined space.
Open end fuel gas and oxygen hoses shall be immediately removed from enclosed spaces when they are disconnected from the torch or other gas-consuming device.

# ELECTRICAL-GENERAL REQUIREM ENTS

# 1926.400(g)
(1) Equipment or circuits that are deenergized shall be rendered inoperative and have tags attached at all points where such equipment or circuits can be energized.
(2) Controls that are to be deactivated during the course of work on energized or deenergized equipment or circuits shall be tagged.
(3) Tags shall be placed to identify plainly the equip ment or circuits being worked on. (11) Operating levers controlling hoisting or dumping devices on haulage bodies shall be equipped with a latch or other device which will prevent accidental starting or tripping of the mechanism.

# BASE-

# 1926.603(a)
(5) A blocking device, capable of safely supporting the weight of the hammer, shall be provided for placement in the leads under the hammer at a ll times while employees are working under the hammer.

# INITIATION OF EXPLOSIVE CHARGES-ELECTRICAL BLASTING
1926.906 (j) In underground operations when firing from a power circuit, a safety switch shall be placed in the perma nent firing line at intervals. This switch shall be made so it can be locked only in the "Off" position and shall be provided with a short-circuit arrangement of the firing lines to the cap circuit.
(1) When firing from a power circuit, the firing switch shall be locked in the open or "Off" position at all times, except when firing.
It shall be so designed that the firing lines to the cap circuit are automati cally short-circuited when the switch is in the "Off" position.
Keys to this switch shall be entrusted only to the blaster.

# PO W ER TRANSMISSION AND DISTRIBUTION

# (d) Deenergizing lines and equipment
(1) W hen deenergizing lines and equipment operated in excess of 600 volts, and the means of disconnecting from electric energy is not visibly open or visibly locked out, the provisions of subdivisions (i) through (vii) of this subparagraph shall be complied with:
(i) The particular section of line or equipment to be deenergized shall be clearly identified, and it shall be isolated from all sources of voltage.

# Appendix C EVALUATION OF EXISTING STANDARDS -INTERNATIONAL, NATIONAL, STATE, CONSENSUS
The follow ing paragraphs compare and e v a lu a te the c u rre n t n a tio n a l, s t a t e , in t e r n a t i o n a l , and consensus stan d ard s r e la t e d to energy c o n tro ls (lo ck o u t/ tag o u ts) fo r accom plishing m aintenance and s e rv ic in g a c t i v i t i e s s a f e ly . S p e c if ic a lly , the g u id e lin e s recommended are compared w ith: OSHA General In d u stry Standards (29 CFR 1910) and OSHA C o n stru ctio n Standards (29 CFR 1926); S ta te Standards (with approved OSHA p la n s ); c r i t e r i a developed in Canada (A lb e rta ), Germany, and B rita in ; and consensus stan d ard s ANSI Z244.1-1982 and NFPA 70E p a r t I I .

# Summary
Appendix Tables C -l, C-2, and C-3 p re se n t an o v e r a ll comparison of the recom mended g u id e lin e s w ith the re s p e c tiv e n a t i o n a l , s t a t e , i n t e r n a t i o n a l , and consensus stan d ard s.
Even though the types of energy a p p lic a b le and the i n d u s tr ie s a ffe c te d v a ry , a c o n sid erab le c o n siste n c y is found in the g u id e l in e s re q u ire d for a l l except th e OSHA n a tio n a l sta n d a rd s and the s t a t e OSHA stan d ard s (with the excep tio n s of C a lifo rn ia and M ichigan). The primary c r i t e r i a elem ents e lim in a tin g energy, secu rin g the means by which the energy is e lim in a te d , v e r if y in g th a t energy has d is s The C a lifo rn ia stan d ard s are a ls o lim ite d to e l e c t r i c a l energy and m echanical motion o f equipment; whereas, the recommended c r i t e r i a cover e l e c t r i c a l , m echanical, and therm al energy.
The e x is tin g A lb erta , Canada, re g u la tio n s lack e f fe c tiv e n e s s sin ce they do not include m echanical motion or therm al energy as a p p lic a b le forms o f energy th a t p ersonnel must be safeguarded a g a in s t.
Also, the A lb e rta re g u la tio n s do not sp ec ify the documenting o f procedures and t r a in in g of personnel as n ec essary req u irem en ts fo r an e f f e c t i v e program for c o n tr o llin g hazards during m ainte nance.
The d r a f t German Accident P rev en tio n S p e c ific a tio n s do not in clude e l e c t r i c a l , chem ical, or therm al as a p p lic a b le forms of energy to be c o n tro lle d during m aintenance and s e r v ic in g .
I n d u s trie s a f fe c te d by the s p e c if ic a t i o n s are lim ite d to "power driven equipm ent" which excludes many i n d u s tr ie s th a t expose workers to hazardous le v e ls of energy during m aintenance.
The German s p e c i f i c a tio n s do not re q u ire v e r i f i c a t i o n th a t hazards have been c o n tr o lle d , docu m enting o f procedures, or t r a in in g of personnel in s a fe work p r a c t i c e s .

# General Industry Lockout Related

# Standard Provisions

# SPECIFICATIONS FOR ACCIDENT PREVENTIONSIGNS AND TAGS
No.

# 1910.145(f)(1)

# STANDARD
(i) The tags are a temporary means of warning all con cerned of a hazardous condition, defective equipment, radiation hazards, etc.
The tags are not to be con sidered as a complete warning method, but should be used until a positive means can be employed to elimi nate the hazard; for example, a "Do not Start" tag on power equipment shall be used for a few moments or a very short time until the switch in the system can be locked out; a "Defective Equipment" tag shall be placed on a damaged ladder and immediate arrangements made for the ladder to be taken out of service and sent to the repair shop.

# REQUIREM ENTS
(10) It is recommended that each power-driven wood working machine be provided with a disconnect switch that can be locked in the off position.
(3) On applications where injury to the operator might result if motors were to restart after power failures, provision shall be made to prevent machines from auto matically restarting upon restoration of power.
(5) On each machine operated by electric motors, posi tive means shall be provided for rendering such con trols or devices inoperative while repairs or adjust ments are being made to the machines they control.

# PULP, PAPER AND PAPERBOARD MILLS

# 1910.261(b)
(4) Lockouts. Devices such as padlocks shall be pro vided for locking out the source of power at the main disconnect switch. Before any maintenance, inspection, cleaning, adjusting, or servicing of equipment (elec trical, mechanical, or other) that requires entrance into or close contact with the machinery or equipment, the main power disconnect switch or valve, or both, controlling its source of power or flow of material, shall be locked out or blocked off with padlock, blank flange, or similar device.
(5) Vessel entering.
Lifelines and safety harness shall be worn by anyone entering closed vessels, tanks, ship bins, and similar equipment, and a person shall be stationed outside in a position to handle the line and to summon assistance in case of emergency. The air in the vessels shall be tested for oxygen deficiency and the presence of both toxic and explosive gases and vapors, before entry into closed vessels, tanks, etc., is permitted.
Self-contained air-or oxygen-supply masks shall be readily available in case of emergency. Work shall not be done on equipment under conditions where an injury would result if a valve were unexpect edly opened or closed unless the valve has been locked in a safe position.

# 1910.261(e)
(2) Slasher tables. Saws shall be stopped and power switches shall be locked out and tagged whenever it is necessary for any person to be on the slasher table.
(10) Stops.
All control devices shall be locked out and tagged when knives are being changed.

# 1910.261(e)(12)
( ii i) Whenever it becomes necessary for a workman to go within a drum, the driving mechanism shall be locked and tagged, at the main disconnect switch, in accor dance with paragraph (b)(4) of this section.

# 1910.261(e) (13) Intermittent barking drums.
In addition to motor switch, clutch, belt shifter, or other power discon necting device, intermittent barking drums shall be equipped with a device which may be locked to prevent the drum from moving while it is being emptied or filled .

# 1910.261(f)(6)
(i) When cleaning, inspection, or other work requires that persons enter rag cookers, all steam and water valves, or other control devices, shall be locked and tagged in the closed or "off" position. Blank flanging of pipelines is acceptable in place of closed and locked valves. Every textile machine shall be provided with individual mechanical or elec trical means for stopping such machines.
On machines driven by belts and shafting, a locking-type shifter or an equivalent positive device shall be used. On opera tions where injury to the operator might result if motors were to restart after failures, provision shall be made to prevent machines from automatically restart ing upon restoration of power.
(2) Protection for loom fixer.
Provisions shall be made so that every loom fixer can prevent the loom from being started while he is at work on the loom. This may be accomplished by means of a lock, the key to which is retained in the possession of the loom fixer, or by some other effective means to prevent starting the loom.
(1) J-box protection.
Each valve controlling the flow of steam, injurious gases, or liquids into a J-box shall be equipped with a chain, lock, and key, so that any worker who enters the J-box can lock the valve and retain the key in his possession. Any other method which will prevent steam, injurious gases, or liquids from entering the J-box while the worker is in it will be acceptable.
(2) Kier valve protection.
Each valve controlling the flow of steam, injurious gases, or liquids into a kier shall be equipped with a chain, lock, and key, so that any worker who enters the kier can lock the valve and retain the key in his possession. Any other method which w ill prevent steam, injurious gases, or liquids from entering the kier while the worker is in it w ill be acceptable. (iii) A main disconnect switch or circuit breaker shall be provided.
This switch or circuit breaker shall be so located that it can be reached quickly and safely.

# 1910.265(e)(1) (iv) Carriage control.
A positive means shall be pro vided to prevent unintended movement of the carriage. This may involve a control locking device, a carriage tie-down, or both.
(2) Before the voltage is applied, cable conductors shall be isolated to the extent practicable. Employees shall be warned, by such techniques as briefing and tagging at all affected locations, to stay clear while the voltage is applied. ( ii i) After all designated switches and disconnectors have been opened, rendered inoperable, and tagged, visual inspection or tests shall be conducted to insure that equipment or lines have been deenergized.

# 1910.268(m)(7) (i)
(iv) Protective grounds shall be applied on the discon nected lines or equipment to be worked on.
(v) Guards or barriers shall be erected as necessary to adjacent energized lines.
(vi) When more than one independent crew requires the same line or equipment to be deenergized, a prominent tag for each such independent crew shall be placed on the line or equipment by the designated employee in charge.
(vii) Upon completion of work on deenergized lines or equipment, each designated employee in charge shall determine that all employees in his crew are clear, that protective grounds installed by his crew have been removed, and he shall report to the designated authori ty that all tags protecting his crew may be removed.

# 2) When a crew working on a line or equipment can clearly see that the means of disconnecting from elec tric energy are visibly open or visibly locked-out, the provisions of subdivisions (i) and (ii) of this subparagraph shall apply:
(i) Guards or barriers shall be erected as neces sary to adjacent energized lines.
(ii) Upon completion of work on deenergized lines or equipment, each designated employee in charge shall determine that all employees in his crew are clear, that protective grounds installed by his -6 7-crew have been removed, and he shall report to the designated authority that all tags protecting his crew may be removed.

# (b) Deenergized equipment or lines
When it is necessary to deenergize equipment or lines for protection of employees, the requirements of para graph 1926.950(d) shall be complied with. -70an nisi TTinni .  rci np^ninv i k k k i:  ri 11 - -- uen ormeii s h i p i v wiiri in  nni*7#-T n r r . nil r

# APPENDIX E REFERENCES SUPPORTING GUIDELINES FOR CONTROLLING HAZARDOUS ENERGY DURING MAINTENANCE
The "Report of the Committee on Electrical Safety Requirements for Employee Workplaces"
 makes specific provisions for performing maintenance functions without benefit of lockout or tagout procedures.
Other supporting references are: In a letter to OSHA from the Printing Industries of America, Inc. , the statement that "much of the equipment currently used in the printing process is designed to be cleaned, and to a lesser degree repaired, while energized" hi^ilights the need to protect workers from ener gized equipment. The only way to protect the worker under these conditions is to be sure the procedures used are safe. Additionally, the ANSI Safety Stan dard for the Lockout/Tagout of Energy Sources  states that "where energized work is required, acceptable procedures and equipment shall be employed to provide effective protection to personnel."
The terms "acceptable" and "effective protection" indicate a definite need to determine that the proce dures used are safe.