Confined Spaces

Question 1

Definition

Answer 1

Any space by design has limited openings for entry and exit.

Question 2

unfavorable natural ventilation

Answer 2

can contain or produce dangerous air contaminants and one which is not intended for continuous occupancy

Question 3

Examples

Answer 3

tanks, vaults or manholes

Question 4

Permit required confined space

Answer 4

1. has the potention to contain a hazardous atmosphere
2. material that has the material for engulphing someone entering the space.
3. has an internal configuration such that anyone entering could be trapped or asphyxited by walls that converge inwardly or a floor that slopes downward and tapers to a smaller cross section

noise radiation electrictiy

Question 5

Examples

Answer 5

storage tanks pits vats electrical manholes vaults boilers pipelines trenches or excavations

Question 6

entering a confined space

Answer 6

A review of the specific guidelines is vital
only allow entry after
 - training and equipment
appropriate ppe
osha;s procedures put into effect
- proper permit issues

Question 7

OSHA

Answer 7

Procedures - OSHA CFR 29 1910.146

designed to make the space safe elimate hazards and to train in safe work practices

Question 8

Preliminary Evaluation

Answer 8

performed prior to site entry
secondary is more detailed to further identify existing hazards to aidd in the selection of appropriate engineering controls and personal PPE for future site eactivities. The evaluation mus tinclude all suspected conditions that are immediately dangerous to life or health - (IDLH) or that may cause serious harm to employees (confined space entry, potentially explosive or flammabvle situation s, visible vapor clouds, etc.).

Question 9

Permit Required Confined Space Entry

Answer 9

Storage tanks, process vessels, silos, vaults, storage bins, hoppers, ship compartments, exhaust ducts , sewers, tunnels, and boilers. A space does not have to be enclosed to be considered a permit-requiored confimed space. Pits, trenches and open topped vats also fit the OSHA description since they may have limited means of entry ane exit, and are not intended for habitation and could possess hazardous atmospheres.

OSHA has determined that individuals who enter permit-required condined spaces are at a significant risk of death or injusry. Therefore, all permit-required confined spaces are to be considered dangerous until proven otherwise.

Question 10

Permit System

Answer 10

The permit system
The permit is a mandatory checklist
Employer must implement a afunctional permit program if a permit- confined space is on the premises. Before entry is authorized, the employer muyst document:
- Measures that have beenb implemented to prevent unauthorized entry.
Hazards that have been identified and evaluated before employee entry.
The means, procedures, and practices necessary for safe permit space entry operations and show these have been developed and jmplemented.

Question 11

Entry Permit OSHA Guidelines

Answer 11

Municipality will develop entry permit

1. permit space to be entered
   q. the purpose of the entry
2. The date and the authorized duration of the entry permit
3. The authorized entrants by name, or a means that will allow the attendant to determine quickly and accurately which authorized attendants are within the space
4. The personnel, by name, servicng as attendants
5. The individual, by name, sercing as entry supervisor, with a space for the signature or initials of the entry super visor who originally authorized entry.

Question 12

Addl

Answer 12

the individual who authorizes the entry must sign the permit. This identifies the party responsible shyloyule any problem arise during entry. It is assumed that the affixing of ones signature to the permit will insure that hte permit process has bben taken seriously and that all protective measures are actually in place. Permits have a definite dureation of effect and are canceled when the entry is over. This will assure that tall entrants and their equipment have exited the space before the space is returned to its normal state. TS permit is also canceled with an emergency develops and/or an evacuation of the space is necessitated.

Question 13

Entry permit time

Answer 13

kept for 1 year. Annual review showing how many entries for a 12 month period. If no entries during the year then no entries or report is required.

Question 14

Personnel Responsibilities in a confined space work area

Answer 14

must be aware of the hazards
1. planning entry and exit procedures
2. rescue and training drills at intervals as determined necessary by the employer
use of testing equipment for atmospheric monitoring
lockout procedures
ventilation
duties of attendant and entrant
safety equipment use

Question 15

Testing and monitoring

Answer 15

Atmospheric monitoring.
The results of this testing will govern every phase of entry.
- oxygen depletion
- flammability
- toxicity
Monituring practices and instruments should gear toward these three central hazards

Question 16

Hazards

Answer 16

3 major
 - oxygen deficiency
less than 
 - flammable is where oxygen is in the air - potentially explosive
-

Question 17

Toxic atmospheres

Answer 17

Substances

• product stored in the space
• work performed in the space
• toxic materials stored in areas adjacent to the space

Question 18

Labeling and Posting

Answer 18

All warning signs shall be printed in english and language of others not able to read in english

• entrances must be posted
• emergency procedures
• phone numbers for response and rescuse teams must be posted in the immediate areas of the confined space.

Question 19

Work Practices

Answer 19

EEs shall review the specific guidelines or standards for appropriate safe entry and emergency exit. These guidelines or standards must be compiled by the qualified person and be definitive on all the prossible hazards in tareas covered by such guidelines.

-

Question 20

Ventilation

Answer 20

one of the greatest hazards is the atmosphere. ventilation is needed when an idlh or nearly idlh atmosphere exists in confined psaces. IFLH means toxis gas levels are above osha;s permissable exposure level , a flammable gas’ concentration is greater than 10% of its lower explosice limit (LEL) or oygen concentration is less than 19.5 % or greater than 23.5 %

Ventilation is not limited to those situation . Very hot environments can be ventilated with cooler air. Atmospheres that contain toxic gases can be ventilated even though the conventratio nis still below PEL. Some sources say that ventilation is adequate when it exchanges the atmosphere in the space 30 times per hour with 12 changes made piror to entry.

Question 21

Atmosphere

Answer 21

Can be altered in many ways
flammable vapors can be absorbed by using activated carbon

The most frequently used method of altering or replacing eh atomosphere is through ventilation .  Specific techniques vary according to:
 - size and orientation of the space
size of the exhaust opening
 - types of vapors to be removed
- source of the replacement air

Regardless of the ventilation technique used , it replaces a contaminated atmosphere with one that is uncontaminated.

Question 22

Ventilation

Answer 22

Typed used

• the effect of the contaminants vapor density
• Application of positive or negative pressure

Question 23

Example

Answer 23

Vertical Tank with methane gas.
The greater the difference in vapor density, the faster natural ventilation witll take place. Natuarally, the reverse flow would occur if the atmosphere in teh container had a vapor density greater than one, the vapor density of air. Many of the gases that need to be ventilated are either present in faily low voncentrations or have vapor densities lose to one.

Question 24

Forced Ventilation

Answer 24

Means that hte natural ventilation is not very effective. It involves a fan, air complressor or other maching.

There are 2 types of forced ventilation:

• Positive pressure ventilation
• Negative-pressure ventilation

Question 25

Natural wind

Answer 25

positive or negative entilate a container. The effectiveness of the natural ventilation depends on:

• the number of openings
• the opening sizes
• the orientation of the ipenings to the wind
• wind speed and consistency

Question 26

Positive pressure ventilation

Answer 26

when a space is ventilated by positive pressure, air is blown into the space, thus pressurizing. The increased pressure forces for the contaminated atmosphereout and allows uncontaminated atmospher in. The scouring action of positive-pressure ventilation also helps to eliminate dead spots where contamination levels can still be high. In many cases, tubes are attached to the output side of the fan, channeling the air to where it is needed. This is very jelpful when the airstream needs to bend, as in manhole ventilation, or when only one opening exists in the container. Otherwise, the turbulence caused between inflow inhibits exchange. By keeping the inflow and outflow gases separate, turbulence is essentially eliminated and efficiency is greatly increased.

Question 27

Negative Pressure Ventilation

Answer 27

The reversw of positive ventilation - the fan is truned around and the contaminated air is drawn out of the container. Again, ventilation is very inefficient, if there is only one ventilation opening.

The ventilation method is dependent upon the equipment available. Most ventilation fans are not explosion proof. if the atmosphere to be removeved from the container is flammable, the use of negatibe pressure ventilation requires frawaing the gas through the fan, which greatly increases the risk of ignition by the fan’s powre.

Many high capacity fans get their poser from an internal combustion enging. if such a fan were used to remove an oxygen-deficient atmosphere, the engine would perform poorly since the atmosphere used by the carbueror would be low in oxygen. Conversely, a runaway situation can result by drawing an oxygen-enriched (or oxidizer) or fuel enriched atmosphere through the fan. Pneumatic powered fans are sometimes used because they do not present an ignition sources and cab ebe very powerful when run with a large industrial compressor located remotely and attached with long air lines.

Question 28

Isolation / Lockout / Tagout

Answer 28

Isolation is specific for each type of confined space. Safety equipment required during this procedure is ddesignated by the qualified person and is dependedt upon the potential hazards involved. ermit required confimed spaces muyst be completely isolated from all other systems by physical disconnection, double block and bleed, or blanking off oall lines. In continuous systems, where complete isolation is not possible, such as ssewers or utility tunnels, specific written safety procedures approved and enforced by the employer are used.

Question 29

Safety equipment and clothing

Answer 29

CPC and PPE is to shield or isolate individuals from the chemical, physical, and biological hazards that may be encountered.  Careful sleection and us eof qdequate PPE for confined space entry should protect the 
 - lungs,
 - skin, 
 - eyes,
 - ears,
 - nose,
 - face, 
- hands, 
- feey
 - head, 
- body,
 - etc.
Of course engineering and administrative controls should be employed before relying on PPE>

Question 30

Addl

Answer 30

no single combination of protective equipment and clothing is capable of protecting against all hazards. Therefore, PPE should be used tin conjunction with other protective methods.

The use of PPE can itself create significant worker hazards, such as heat stress, physical and psychological stress, and impaired vision, mobility, and communication. In general, the greater the level of PPE protection, the greater the assiciated risks. For any given situation, equipment and clothing shoul dbe selected that provide an adequate level of protection. Overprotection, as well as under protection, can be hazardous and should be avoiuded.

Question 31

Confined space rescue

Answer 31

Condined space emergencies are among the leading causes of multiple deaths in the workplace. in most cases, an emergency begins with one or two people succumbing to a confined space hazardous exposure. Then, untrained and/or unprotected rescuers add to the problem by entering the space an dbecoming victims themselves.

In fact , about 60% of victims are would-be rescuers. Additionally, a majority of these individuals are supervisors and/or seniour personnel who should know better. Oddly enough there are cases where the intial entrants survive and the would be rescuers die. With this in mind, it appears that the greatest single piece of advise to be passed along is to “resist the overwhelming temptation to try to save a colleague bny entering the space unprotected.”

Question 32

On-site Rescue Teams

Answer 32

Personnel assisgned to an in-plant rescur team must be provided with, and tained in the proper use of the personal protective equipment necessary for makeing rescues from the employer’s permit spaces.

The employer must ensure that the on-site rescue team is trained to perform the assistnwed rescue functions and to be authorized confined space entrants. Rescue teams are required to practice making permit=space rescues at least once every twelve months by means os simulated rescue operations. In these simulated rescue opeation, rescuers remove dummies, mannequins or personnel through representative openings and portals. The size, configuration , and accessibility of thise openings should closely resenble those of the permit spaces from which rescues may be required.

Question 33

Rescue team

Answer 33

thos persons whom the employer has designated prior to any permit-required confined space entry to perform rescues from confined spaces.

Question 34

Outside resuce services

Answer 34

OSHA is aware that, from the viewpoint of elapsed time, in-plant rescue services are perferred . OSHA also realizes that not all employers have the equipment and/or the personnel for such a team. Idfan outside rescue service is to be used , the employer must evaluae the following before a rescue becomes necessary.
- the rescue service
s response time
- Its continuous availability dureing the entry
- its rescue capabilities

Question 35

3 types of rescus

Answer 35

can be employed in the confimred space setting:
- self rescue
non entry rescue (external)
entry rescue (internal)

Question 36

Self Rescue

Answer 36

An entrant recognizes a hazardous exposire and is able to exit from the space with no assistance. Many ties self-resuce resuls bevause an entrant feels ill. in this situation, the assumption is that a hazard within the space is causing the problem and that evacuation is necessary until the problem is identified.

Obviously, self rescue has many advantages ove the other two forms of rescue. With self-rescue, emergency rescue personnel do not have to enter the space. Risky extrication and/or removal techniques are not required if self-rescue can be done. Also, b y virtue of the fact that the individual is still conscious, the chances that the entrant will recover from the emergency are good. Hazard recognition can prevent serious exposure and injury.

Question 37

Non-entry rescue

Answer 37

is rescue perfomed from outside the space. Prior to entry, retrieval / lifelines and body harnesses should be in plae in the event that conditions change. In most cases, non entry rescue involves removal using these lines. It is important to plan and condusc the entry with this form and erescue in mind. Pulley systems, tripoids, and space entry ways should be arranged so that there is little chance that lines can tangle.

Non-entry rescue cannot be used for an individual who is entangled, trapped or bound-up within the space. It can be used for engulfment (burying) situations as long as the amount of engulfing material is small enought to allow the victim to be unearthed using the line tension.

Question 38

Entry Rescue

Answer 38

the form of rescue that peresnts the greatest risk to the rescuer. It entails actually placing an individual into the hazardous space. Entry rescues should be avoided whenever possible. If entry rescue cannot be avoided, the SCBA lifelines harnesses, retreval systems and appropriate levels of protective clothing are required.

Question 39

Medical issues

Answer 39

everyone assosicated with confined space operations should hava a basic understanding of the types of medical emergencies thaty they may encounter. To effectively do this, it is necessary to recognize the potential problems, be able to activate emergencey mefdical services in your plant or municipality and provide first aid prior to the arrival of medically trained personne.

Question 40

OSHA

Answer 40

Trained in CPR an dbasis first aid. At least one individual with current cerfgification should be available dureing rescue operations. All individuals associated with confined space operations also need to know the location and operation of emergency medical supplies and equipment. Itt is the attendant
s job to summon emergency medical assistance in the event of a medical problem.

Question 41

Hear t Attach

Answer 41

chest pain, shortness of breath, nausea, and weakness, heart attack is one of the greatest medical killers of industrial and municipal workes. Usually the onset of severe chest pain is fairly rapit but any chest p[aing should be cause for concern. Appropriate treatment includes immediate removal from the confined space, early actif8iation of EMS rest oxygen administration and CPE if cardiac arrest occurs.

Question 42

Asphyxia

Answer 42

Asphyxia - occurs when the body is deprived of oxygen for one reason or another. As we have seen, engulfment or oxygen-deficient atmospheres are probably tthe two most common causes of asphyxia. Usually the person unconsious, cyanotic (blue in color), and not breathing. Obviously, initiation of mouth to mouth resuscitation and CPR (if the heart has stopped) is critical for the patients survival. This must not be done while the patient is in the confined space.

Question 43

Asphyxia

Answer 43

Asphyxia - occurs when the body is deprived of oxygen for one reason or another. As we have seen, engulfment or oxygen-deficient atmospheres are probably tthe two most common causes of asphyxia. Usually the person unconsious, cyanotic (blue in color), and not breathing. Obviously, initiation of mouth to mouth resuscitation and CPR (if the heart has stopped) is critical for the patients survival. This must not be done while the patient is in the confined space.

Question 44

Chemical Toxicity

Answer 44

a person who inhales a toxic chemical and suffers acute effects will probably have a shortness of breath as the primary symptom. This is especially truek if the chemical is an irritant. Chemical asphyxiates usually cause cyanosis and absence of breathing.
Regardless of the type of chemical inhaled, removal of the individual from the space is the first priority followed by EMS activation . CPR may be necessary if the victims heart has stopped beating. Rescuers must be careful not to contaminate themselves with the toxic chemical by coming into unprotected contact with the patient. If the chemical was absorbed, removal of clothing and decontamination are necessary.

Question 45

Burns

Answer 45

Confined space entrants can suffer everything from minor burns to massive burns caused ny flash fire and explosion. Removal from the space and EMS avtiviation are initioal priorities. With minor burns, ointments or salves can be used, but they shoud not be appied to major burns. Major burns require medical attention and infection is the primary voncern. The patient should be kept warm. The burns must be cleansed and dressed as soon as possible but by a physician. Respiratory complications are common for confirned space fire victims.

Question 46

Fractures

Answer 46

Common injuries in confimed spaces. Fracturs should be immobilized if conditions within the space permit. If not, evacuation of the patient from the sace should proceed as carefully as possible. A patient who has a fracture because of a fall should also be evaluated for other more serious internal injuries . In most cases, fractures of the extremeties do not present a life-threatening situation.

Question 47

Lcerations

Answer 47

3 primary concerns:

• Blood loss
• Infection
• Possible exposure to contaminated blood by the rescuer

In most instances blood loss from lacerations can look severe but be in reality not so significant. Severe arterial belleding on the other hand is life threatening. By applying direct pressure bleeding can usually be stopped. Obviously, initial treatment includes evacuation from the space an prompt WMS notification. A company nurse or physician should evaluate any employee for potential infection if he or she sustanins a laceration in a confined space.

Question 48

Other medical considerations

Answer 48

preventative care for those individuals who enter confined spaces is highly recommended. Especially screening physicals. Immunizations should be kept up to date . Any type of inzjuuy or hazardous material exposure should be documented and evaluated.

Worker
s compensation benefits, as well as effective medical care, depend on promptly filling out the necessary forms and reports. Prevention of injury is the ballmark of the permit system. The permit safety measures, if taken seriously will greatly reduce the chance for a confined space medical emergancy.

Question 49

Excavation

Answer 49

OSHA issued its first excacation and trenching standard in 1971. OSHA has amended the Standard several times to increase worker protection and to reduce the frequency and severity of the excatation accidents and injuries. Despite these efforts, excation related accidents resulting in injuries and fatalities continue to occur.

Question 50

Scope and application

Answer 50

OSHAs revised rule applies to all open excavations made in the earth’s surface, which includes trenches.

According to the OSHA Construction health and safety standard, a trench is referred to as a narrow excaation made below the surface of the ground in which the depth is greater than the width - the width not exceeding 15 feet. An excavatiuon is any human made cut, cavity, trench or depression in the earth’s surface formed by earth removal. This can include excavations for anything from cellars to highways.

Question 51

Planning for safety

Answer 51

many on the job accidents are a direct result of inadequate planning. Correcting shoring sloping

Question 52

Planning for safety

Answer 52

many on the job accidents are a direct result of inadequate planning. Correcting shoring sloping mistakes after work has begun slows down the operation, adds to the cost, and increases the possibility of an excavation failure. The contractor should build sfety into pre bid planning in the same way all other pre bid factors are considered. it is a good idea for contactors to develp a sefety checklist before preparing to bid to make certain that information about ht ejob site is adequate and that all needed items will be made available.

Contractors should also make sure that they have enough space to safely dig their excavations in relation to p property lines, neighboring utilities, adjacent structures, etc and as the project scope changes these considerations must be taken into account and budgeted for. In general, the deeper the excvation the wider it needs to be and the more spoils will be generated. otherwise shoring systems likely need to be employed which takes additional planning and expense.

Question 53

Pewliminary Information to Gather

Answer 53

Requires employer to determine the estimated location of utility installations such as sewer , telephone, fuel electric, waterlines, or any toerh underground installations that can be encountered while digging. Also, before starting, the contractor must contact utility companies or involved property owners and inform them, within their established or customary local response times. The contracoter must also ask the utility companies or owners to identify the exact location of all underground installatio9ns.

Question 54

ERs Safety and health program

Answer 54

It is important for the contracotr to establish and maintain a safety and health program for the worksite. The program should provide adequate policies, procedures, and practices to protect employees from, and enable them to recognize job-related safety and health hazards.

An effective program includes provisions for the systematic identification, evaluation, and prevention or control of workplace hazards. The contractor must identify potential hazards that can arise from foreseeable conditions, both generally within the site and specific to certain tasks. The program can be written or verbal, but it should reflect the unique characteristics of the job site.

Question 55

EE Operating Equipment

Answer 55

no employee should operate a piece of equipment wiyhout being properly trained to handle it and fully alerted to its potential hazards in the training as well as the site safety and heal programn it is also important to incorporate procedures for fast notification and investigation of accidents.

Question 56

On the job evaluation

Answer 56

Thestandard requires that a competent person inspect, on a daily basis, excavations and the adjacent areas for possible cave-ins, failures of protective systems and equipment, hazardous atmospheres, or other hazardous conditions. If these conditions are encountered, then exposed employees must be removed from the hazardoius area until the necessary safety precautions have been taken.. Inspections are also required after natural or human caused events which can increase the potential for hazards.

Question 57

On the job evaluation

Answer 57

Thestandard requires that a competent person inspect, on a daily basis, excavations and the adjacent areas for possible cave-ins, failures of protective systems and equipment, hazardous atmospheres, or other hazardous conditions. If these conditions are encountered, then exposed employees must be removed from the hazardoius area until the necessary safety precautions have been taken.. Inspections are also required after natural or human caused events which can increase the potential for hazards.

Question 58

Cave-ins and Protective Support Systems

Answer 58

Excavation works are exposed to many hazards, but the chief hazard is the danger of cave-ins. OSHA requires that all excavations, employees exposed to potential cave-ins mustbe protected by the following:

• sloping or benching (terracing / stepping)
• shielding
• ahoring / bracing

Designing a protective system can be complex because of the number of factors involved, for example, soil classification, depth of cut, water content of soil, changes due to weather an cclimate, or other operations in the vicinity.

Question 59

Cave-ins and Protective Support Systems

Answer 59

Excavation works are exposed to many hazards, but the chief hazard is the danger of cave-ins. OSHA requires that all excavations, employees exposed to potential cave-ins mustbe protected by the following:

• sloping or benching (terracing / stepping)
• shielding
• ahoring / bracing

Designing a protective system can be complex because of the number of factors involved, for example, soil classification, depth of cut, water content of soil, changes due to weather an cclimate, or other operations in the vicinity.

Question 60

Safety Precautions

Answer 60

requires employers to provide support systems such as shoring, bracing or underpinning to ensure the stability of adjacent structures such as buildings, walls sidewalks or pavement.

The standard probibits excacation below the level of the base or footing of any foundation or retaining wall unless:
- a support system such as underpinning is provided
- the excacation is in stable rock
a registered professional engineer determines that the structureis sufficiently removed from the excavation and that the excacation will not pose a hazard to employees.

Excavations under sidwalks and pavement are also prohibited unless an appropriately designed support system is provided or another effective method is used.

Question 61

Safety Precautions

Answer 61

requires employers to provide support systems such as shoring, bracing or underpinning to ensure the stability of adjacent structures such as buildings, walls sidewalks or pavement.

The standard probibits excacation below the level of the base or footing of any foundation or retaining wall unless:
- a support system such as underpinning is provided
- the excacation is in stable rock
a registered professional engineer determines that the structureis sufficiently removed from the excavation and that the excacation will not pose a hazard to employees.

Excavations under sidwalks and pavement are also prohibited unless an appropriately designed support system is provided or another effective method is used.

Question 62

Materials and Equipment

Answer 62

The employer is responsible for the safe condition of materials and equipment used for protective systems at excavations. Defective and damaged materials and equipment can result in the failure of a protective system and cause excavation hazards.

Question 63

Installation and removal of protective systems

Answer 63

standard requires th following consederations for the protection of employees when installing support systems:

• securely connect members of support systems.
• safely install support systems
• never overload members of support systems
• install other structural members to carry loads imposed on the support system when temporary removal of individual members is necessary

Question 64

Installation and removal of protective systems

Answer 64

standard requires th following consederations for the protection of employees when installing support systems:

• securely connect members of support systems.
• safely install support systems
• never overload members of support systems
• install other structural members to carry loads imposed on the support system when temporary removal of individual members is necessary

Question 65

Trenches

Answer 65

standard permits excacation of 2 feet or less below the bottom of themembers of a support or shield system if the system is designed to resist the forces calculated for the full depth. and there are no indication, while the trench is open, of a possible cave in below the suppor t system bottom. Also the installation of support systems must be closely coordinated with the excavation of the trenches.

Question 66

Other hazards

Answer 66

in addition to cave in hazards and secondary hazards related to cave ins, there are other hazards from which workers must be protected during excavation related work.

Question 67

Other hazards

Answer 67

in addition to cave in hazards and secondary hazards related to cave ins, there are other hazards from which workers must be protected during excavation related work.

Question 68

Falls and equipment

Answer 68

to protecct employees from these hazards, employers must take the following precautions:
- Keep materials or equpment that might fall or roll into an excavation at least two feet from the edge of excavations, or have retaining devices or both
prohibit employees from working on faves of sloped or benched excavations at levels above other employees, unless employees at lower levels are adequately protected from the hazard of falling rolling or sliding material equipment.
prohobit employees from going beneath loads that are handled by lifting or digging equipment.

Question 69

Water accumulation

Answer 69

prohibits ees from working in excacations where water has accumulated or is accumulating. unless adequate protection has been taken. If water removal equipment is used to control or prevent water accumulation, a compentat person must monitor the equiment and operation s to ensure proper usage . When water infiltrates an excavation the soil needs to be reclassified.

OSHA also requires that diversion ditches, dikes or other suitable means be used to prevent surface water from entering an excavation. Adequate drainage of the area adjacent to the excavation is necessary. Also, a competent person must inspect excacvations subject to heavy rain runoff.

Question 70

Hazardous Atmospheres

Answer 70

Before an ee is allowed to enter an excacation, a competent perseon must test if it is over four feet deep or if oxygen deficiency or a hazardous atmosphere exists or could reasoabley be expected to exist. If hazardous conditions exist, controls such as proper respiratory protection or ventilation must be provided. Also, controls used to reduce atmospheric contaminants to acceptable levels must be tested regularly.

Question 71

Access and Egress

Answer 71

the employere mur provide safe access to and egress from all excavations.

According to the OSHA regulations, when employees are requried to be in trench excavations four feed deep or deeper adequate meansof exit such as ladders, steps, ramps or other safe means of egress must be pro=vided and be within 25 feet of lateral travel. If structural ramps are used as a means of accessor egress, a competent person qualified in structural design must plan them. Also, structural members used for ramps or runways mus t be uniform in thickneess and joined in a manner that prevents tripping or displacement.

Question 72

Avoid Risk

Answer 72

Trenching and excavation work presents serious risks to all workers involved. The greatest risk, and one of primary concern, is that of a cave-in. Furthermore, when cave-in accidents occur, they are mush more likely to result in work e fatalities than other excavation-related accidents. Strict compliance, however, with all sections of the Standard will prevent and/or greatly reduce the risk of cave-ins as well as other excavation-related accidents.