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When
OSHA Comes Knocking:
Preplanning Reduces Headaches and Fines |
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With thorough preplanning and the proper designation of a competent person, excavation work can be accomplished both profitably and safely.
OSHA
Requirements All of us have read about excavation cave-ins resulting in injuries, and we intuitively know that working inside deep trenches or pits is dangerous. It is often assumed that these injuries are the normal costs of doing business within the excavation industry. Personal injury is only one aspect of the "costs" associated with unsafely executed earthwork. Schedule slippage and delays from sidewall collapse, runoff inundation, or damage to utilities/surface structures are far more frequent and costly to excavators than the publicized injuries in the news. In addition, the hidden costs of inspection fines levied by the Occupational Safety & Health Administration (OSHA) and the accompanying bad publicity make it apparent that proper safety planning prior to breaking ground is essential, both for the health of employees and the long-term viability (and profitability) of your company. Why do so
many excavation contractors fail to properly preplan? One reason is
tradition: Excavation is a simple activity; it has always been done
in the same way, so no additional time during the up-front project design
or planning phase is invested. Every time a project crew is allowed
to "work it out" in the field and no one gets hurt and OSHA
does not show up, this traditional view is reinforced. Then when something
does go wrong, resulting in delays, injuries, or citations, it is written
off as an unavoidable project loss, and work continues with the belief
that the profit will be made up on the next project. The realization
never occurs that these project losses were avoidable and that properly
performed and implemented preplanning would have prevented these losses
and padded the project's bottom line. In summary, excavation-safety
preplanning and execution simply make good business sense. Excavation-safety preplanning begins with a review of OSHA's excavation standard, 29 CFR 1926.650-.652, Excavations (Subpart P). The standard contains many different requirements, as well as several appendices, that make it very confusing at first glance. The following information summarizes the main requirements in order to help contractors prepare for expected or surprise OSHA inspections. Prior to digging, the contractor shall identify and locate all underground utilities. This requirement is to prevent backhoes and excavators from accidentally severing telephone, data, water, or gas lines. Should this occur, disruption of local services and lost project profit are the best results that can be hoped for. Equipment-operator injury is a more serious outcome if a gas explosion occurs. All surface "encumbrances"-signs, trees, fences, poles, sidewalks, etc.-must be protected during the dig. Since undercut items suddenly can give way, striking employees and bringing down electrical lines, compliance with this requirement prevents injury or electrocution. All excavating equipment must maintain a minimum of 10 ft. from overhead power lines rated 50 kV or less, with 0.4 in. of clearance added for every kV over 50. Adherence to this requirement will prevent the equipment from contacting the energized line, and it will minimize the possibility of electrical arcing. Employees exposed to vehicular traffic must wear a high-visibility vest, and the excavation must be protected from traffic. If vehicular movement around the excavation edge presents the possibility of running into the hole, or if the equipment operator does not have a clear view of the edge, then stop logs or other physical barriers should be placed far enough back from the edge that impact with them will alert the operator to stop the equipment. Any excavation left unattended must be barricaded, fenced, or otherwise protected against accidental entry from pedestrians. If the excavation is in a remote location where visitation by residents is unlikely, a barricade of posts and warning tape, with a sign, is sufficient. If the excavation is in a traveled area, however, a physical barrier such as a fence must isolate it. In these locations, an excavation left unattended is considered to be an "attractive nuisance"-a legal term that implies a responsibility of the hazard creator to physically prevent entry by the public. The contractor must designate a competent person to assess the excavation and determine that it is safe for project personnel to enter and work. This person must be present on-site when the excavation is entered, to assess the excavation daily, as well as after each significant weather event or hazard-increasing occurrence that could affect the excavation's safety. Sidewall exposure to drying can change excavation conditions, rain or runoff can enter the excavation, or cracking and spalling of the excavation sidewalls can occur at any time. Additionally, site activities such as pile driving, jackhammering, or other vibration-inducing tasks could cause cracking or sidewall instability. A "competent person" is, by OSHA definition, someone who is capable of identifying existing and predictable hazards in the surroundings or capable of identifying working conditions that are unsanitary, hazardous, or dangerous to employees and who has authorization to take prompt corrective measures to eliminate them. The designated competent person must understand the responsibility that this role carries. The competent person is responsible for the safety of all excavation workers and typically will be the first employee interviewed by OSHA during an accident investigation. The lack of a designated, trained, competent person available during an OSHA inspection will frequently result in a citation. The competent person may have gained this knowledge through prior field experience, completion of formal safety training, or both. The individual designated as the competent person must willingly accept this role. Given today's emphasis on time and schedule, this regulation is very logical. It is one of the most important of all the OSHA regulations, yet it is frequently neglected by many small contractors. Without a knowledgeable onsite authority figure, safety just isn't going to happen. The contractor must provide a safe means of entering or exiting any excavation over 4 ft. deep. Potentially acceptable methods are ladders, ramps, manbaskets, or stairs. This makes sense; think about how you would get into a trench without a ramp or a ladder. You would sit down on the edge and slide in, or jump down. Jumping is dangerous, and sliding places pressure on the sidewall. And when exiting, you would have to place your arms up over the surface and attempt to sling your legs over the lip. Again, you are placing pressure on the sidewall face and generating vibration, both of which are known to cause cave-ins. If you are using a straight ladder, make sure that the ladder extends out of the excavation at least 3 ft. This allows the user to climb out of the excavation and step off onto the surface instead of having to partly climb out. If you are installing a ramp, cut the ramp at such an angle that workers can easily walk out, upright, without using their hands to secure their position. A means of egress shall be located within 25 ft. of the worker(s). This means that any excavation worker must be able to reach the provided means of exit by moving laterally no more than 25 ft. The rationale for this requirement is that in the event of a cave-in, it is critical that the worker exits within a few seconds since there is often a second (or even third) successive cave-in. Also, having the means of exit close at hand lowers the probability in long trenches that a collapse of the sidewall will block the exit travel path. If the excavation is longer than 50 ft. and workers will be moving throughout the length, then more than one exit point will be necessary: a frequently unplanned for, and often cited, requirement. If employees must cross over the open excavation (trench), a safe means shall be provided so that the employees do not have to jump. An obvious requirement, and one that is often ignored. If a trench is 100 ft. long and employees will have to move about on both sides, they are not going to walk around the end-they are going to step or jump across. This is dangerous and can be prevented easily by placing a suitable wooden walkway across the trench. If, however, employees must cross over an open excavation at a height of 6 ft. or more, a walkway with standard guardrails (toprail 39-45 in. high and midrail halfway down) must be provided. No workers shall enter or work in excavations where standing water is visible unless adequate protection is afforded. The presence of standing water indicates that at least part of the excavation floor and probably the lower sidewalls are saturated and thus have a diminished degree of soil cohesion-a prime candidate for a cave-in. The water must be pumped out before workers enter. Rainwater runoff can be prevented from entering in the first place by scraping some initial spoil to form diversion dikes along the outside border. Also, saturated soils are Type C (see below) by definition. The removed spoil shall not be stockpiled closer than 2 ft. from the excavation's edge. There are several reasons for this direction: (1) placing the spoil at the edge hides the adjacent surface and makes visual detection of cracks impossible; (2) spoil too close to the edge permits soil, rocks, debris, etc. to fall in the excavation and on top of workers; and (3) the weight of the spoil pile will place a tremendous additional downward force on the already unsupported excavation sidewall, increasing the possibility of failure. In excavations over 4 ft. in depth, a potential for the accumulation of hazardous gases or vapors exists. Sources of hazardous atmospheric contaminants include the exhaust of equipment in or near the excavation, lateral movement through soils of natural gas, gas-line ruptures, and landfill gases (when excavating in landfills). If there is any reason to suspect that a toxic atmosphere is, or is likely to be, present in the excavation, then the atmosphere must be tested prior to working in it. A multigas monitor (oxygen, flammability, and carbon monoxide) would be appropriate for most situations if testing is required. Document the time, location, tester, and readings. The reason that pits and trenches are potential contaminant traps is because most harmful gases and vapors are heavier than air and will settle in low places, such as excavations. OSHA does not mandate that all 4-ft.-plus excavations be examined for atmospheric contaminants; it is only necessary when the possibility is real. If the excavation does contain a hazardous atmosphere, then refer to the OSHA standard, Permit-Required Confined Space, 29 CFR 1910.146, for additional requirements. If the excavation is over 5 ft. deep, a protective system shall be employed to prevent cave-in. This requirement is the heart and soul of excavation safety and yet is the most misunderstood of all the OSHA excavation requirements. This requirement mandates that all excavations greater than 5 ft. deep be shored, sloped, or otherwise physically prevented from collapsing. It does not state that excavations under 5 ft. are always safe and need no protective system. The correct interpretation is that if project site conditions are appropriate-such as cohesive soil, lack of vibration, short-term opening, upright body positioning during work-shallow excavations under 5 ft. may not need additional protective systems, based on a knowledgeable assessment by the competent person. Historically contractors have incorrectly assumed that sloping or shoring is only required on excavations deeper than 5 ft. Since the language of the standard allows for entry into a nonshored or nonsloped excavation less than 5 ft. deep if deemed safe by a competent person, then this obviously requires a designated competent person to make that determination on-site. The contractor should be aware that many cave-ins and injuries result from shallow-excavation failures (primarily narrow trenches), and any subsequent OSHA investigation will begin with determining whether a competent person performed an assessment prior to worker entry. Therefore, written assessment notes should be maintained. If a protective
system is necessary, then sloping, shoring, shielding, or another equivalent
method shall be employed to handle the soil stresses imposed. The contractor
has three basic options to prevent excavation failure: (1) sloping the
sidewalls such that the threat of collapse is eliminated, (2) holding
back the sidewalls by installing shoring, or (3) placing a prefabricated
protective metal shield (trench box) in the excavation where the workers
are placed. (For detailed information on the specific requirements of
sloping, shoring, or trench boxes, including engineering data, consult
29 CFR 1926.652 and the accompanying Appendices A-F.) See the sidebar
for a summary of each of these options. Preplanning: A Suggested Method Implementation of preplanning can minimize project delays, disruption, noncompliance costs, and injuries. One method of obtaining consistency in the preplanning process is to employ a checklist at the proposal workup stage. An example of an excavation checklist follows and may be modified to suit the needs of the individual contractor. It also may be easily modified for use during the excavation as a check to verify that all proper safety measures are continuing. It should
be noted that OSHA requirements applicable to excavation work, but not
contained in the excavation standard, also have been included in this
worksheet. Information on the different types of soil manual field tests
is contained in Appendix A of 29 CFR 1926.652 and should be read prior
to attempting. If soil field classification will be performed, a pocket
penetrometer should be purchased for use in determining the unconfined
compressive strength. Note: You may print out the worksheet as it appears below on this Web page. Alternately, you may wish to download a PDF file of the worksheet, which better reflects the format of the one that appears in the print version of GX Magazine. Download
a PDF file of the Preplanning Worksheet. PREPLANNING WORKSHEET: EXCAVATION/TRENCHING
Employee Training and Pre-Excavation Briefing Does this job require special training: YES__ NO__ Safe excavation and rescue training conducted on: ______DATE Mandatory pre-excavation briefing conducted on: ______DATE Soil Classification Will the competent person classify the soil based on its properties and site conditions? YES__ NO__ If yes, continue. If no, then soil is assumed to be Type C; skip to Electrical Safety. Based on visual observation, which best describes the soil in this excavation? Stable Rock_____ Cemented Soil_____ Cohesive Soil_____ Granular Cohesionless_____ Layered System_____ Granular Soil_____ Based on visual observation, which best describes the moisture condition of the soil? Dry Soil_____ Moist Soil_____ Wet Soil_____ Saturated Soil_____ Is a pocket penetrometer available for use on-site? YES _ NO _ N/A__ If yes, what is the average tons per square foot of the soil in this excavation? _____ tsf Based on at least one manual test, what classification is the soil in this excavation? Stable Rock_____ Type A Soil_____ Type B Soil_____ Type C Soil_____ What manual test was used to determine the soil type? Plasticity_____ Dry Strength_____ Thumb Penetration_____ Other (list)___________________________________________ Electrical Safety Are all electrical devices grounded and/or GFCI protected? YES__ NO__ N/A__ Surface Encumbrances Have all surface encumbrances that are located so as to potentially create a hazard to employees been removed or supported as necessary to safeguard employees? YES__ NO__ N/A Underground Installations Have the estimated locations of all underground installations been determined prior to excavation? YES__ NO__ N/A__ Have utility companies been contacted and advised of proposed work? YES__ NO__ N/A__ If underground installations are exposed, have they been protected, supported, or removed while excavation is open? YES__ NO__ N/A__ Access and Egress Are stairways, ladders, or ramps provided every 25 ft.? YES__ NO__ N/A__ Are structural ramps that are used for access and egress of equipment and/or personnel designed by a competent person qualified in structural design, and are they constructed in accordance with the design? YES__ NO__ N/A__ Exposure to Vehicular Traffic Are personnel who are exposed to public or project vehicular traffic wearing reflectorized or high-visibility vests? YES__ NO__ N/A__ Exposure to Falling Loads Are employees prohibited from standing underneath loads handled by lifting or digging equipment? YES__ NO__ N/A__ Warning Systems for Mobile Equipment Are warning systems utilized when mobile equipment is operated adjacent to or at the edge of an excavation? YES__ NO__ N/A__ If yes, which type if being used? Hand Signals_____ Stop Logs_____ Earthen Berm_____ Other (list)________________________________ Testing for Hazardous Atmospheres Are the atmospheric hazards that can be reasonably expected to exist in excavations greater than 4 ft. deep tested and controlled? YES__ NO__ N/A__ Is testing conducted as often as necessary to ensure safety of personnel? YES__ NO__ N/A__
Emergency Rescue Equipment Is emergency rescue equipment, such as a self-contained breathing apparatus, a safety harness and line, or a basket stretcher, readily available and attended when hazardous atmospheric conditions exist? YES__ NO__ N/A__ Protection From Hazards Associated With Water Accumulation Is water being controlled or prevented from accumulating in an excavation by the use of water-removal equipment? YES__ NO__N/A__ Is operation of the water-control equipment being monitored by a competent person? YES__ NO__N/A__ Stability of Adjacent Structures Are support systems, such as shoring, bracing, or underpinning, provided to ensure stability of adjoining structures (i.e., buildings, walls) endangered by excavation activities? YES NO N/A Has the support system been designed by a registered professional engineer? YES__ NO__N/A__ Protection of Employees From Loose Rock or Soil Are the employees protected from equipment and excavated or other material by placing this material a minimum of 2 ft. from the edge of excavations or by the use of retaining devices? YES__ NO__ N/A__ Inspections (Use this section for safety inspections) Are daily inspections of excavations, where employee exposure can be reasonably anticipated, being done by the competent person? YES__ NO__ N/A__ Are inspections being performed by a competent person after every rainstorm or other hazard-increasing occurrence? YES _ NO__ N/A__ Are employees removed from the excavation if the competent person finds evidence at any time of a situation that could result in a possible cave-in, protective-system failure, a hazardous atmosphere, or other hazardous conditions? YES__ NO__N/A__ Fall Protection Are standard guardrails provided on walkways and bridges that cross over 6-ft.-plus excavations? YES__ NO__ N/A__ Are all excavations accessible to the public adequately barricaded or covered when unattended? YES__ NO__ N/A__ Shoring and Other Protective Systems Have all shoring and other protective systems been designed by a registered professional engineer or accompanied by tabulated data from the manufacturer? YES__ NO__ N/A__ Are shoring and other protective systems checked and measured each day to detect movement and possible failure? YES__ NO__ N/A__ I have inspected the excavation described in this checklist:
(Signature of Competent Person) (Date) Copy: Project File  Conclusion With thorough preplanning and the proper designation of a competent person, excavation work can be accomplished both profitably and safely. There is no shortcut to avoiding the scrutiny of OSHA or the occurrence of injuries. Preplanning serves as the best and only effective preparation for a surprise visit from OSHA. Completion of an excavation checklist, such as the example given, ensures that the principal requirements of the OSHA standard have been considered and addressed. One last
note: If questions concerning excavation compliance arise, do not hesitate
to contact your local OSHA office. OSHA representatives are available
for consultation and generally provide accurate information, and these
contacts do not result in inspections (but will certainly help prevent
citations if one does occur).
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