Under OSHA 29 CFR 1926 Subpart P, when must a trench generally have a protective system such as sloping, shoring, or shielding?
Excavation
Question · Easy
How deep before you need a trench box?
Short
In a trench 4 ft or more deep, OSHA requires a stairway, ladder, ramp, or other safe means of egress so that no worker must travel more than what lateral distance to exit?
Unless a retaining device is used, OSHA requires excavated spoil and other materials to be kept at least how far from the edge of an excavation?
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Who must inspect excavations, adjacent areas, and protective systems daily before workers enter, and after events that could increase hazards?
Before excavating for underground tanks or product lines in Mississippi, what is the primary purpose of contacting Mississippi 811?
Divide by twenty-seven
Except for allowed emergency work, Mississippi excavators must give MS811 how much advance notice before beginning excavation?
OSHA soil classification for selecting sloping and shoring groups materials primarily as:
Question · Medium
Which OSHA soil type is generally the least stable and requires the flattest maximum allowable simple slope for excavations 20 ft or less deep?
For simple sloping of excavations 20 ft or less deep, what is the OSHA maximum allowable slope in Type B soil?
At what excavation depth does OSHA require sloping, benching, or other protective systems to be designed by a registered professional engineer, or based on tabulated data prepared or approved by an RPE?
Question · Hard
According to common PEI RP100 practice, the bottom of a UST excavation should typically be covered with bedding backfill to a depth of at least:
PEI RP100 practice generally requires at least how much approved backfill between adjacent underground tanks and between a tank and the excavation wall?
Why must a UST excavation be large enough to provide clear space around the tank shell?
What is a primary reason to avoid using native clay clods, frozen soil, or large rocks as primary backfill around a UST?
When placing an underground tank, why should the tank never be rolled or dropped into the excavation?
In high-groundwater or flood-prone Mississippi sites, what excavation and installation issue must be specifically controlled for empty or partially empty USTs?
In areas subject to vehicle traffic, PEI RP100-type cover over a UST commonly includes which of the following combinations?
In areas not subject to vehicle traffic, PEI RP100-type cover over a UST commonly includes:
Unless the manufacturer specifically allows a greater depth, PEI-type maximum cover over the tank top is commonly about:
During UST excavation near an existing building foundation, what is a critical site-protection concern under NFPA 30 tank-location principles?
What color markings typically identify buried electric lines after an 811 locate, and what should the excavator do if unexpected unmarked utilities are found?
A tank excavation will be 10 ft deep in Type C soil and sloped on both long sides using OSHA's maximum simple slope. If the bottom is 12 ft wide, what is the minimum top width of the excavation?
A rectangular tank excavation measures 30 ft long, 14 ft wide, and 12 ft deep. What is the excavated volume to the nearest cubic yard? (27 cubic feet = 1 cubic yard)
An excavation contains 4,176 cubic feet. A cylindrical tank occupying 1,357 cubic feet will be set in the hole. About how many cubic yards of backfill are needed to refill the hole to original grade, ignoring pavement and compaction settlement?
Why must groundwater be controlled during UST excavation and backfill rather than allowing the hole to remain flooded?
What is the primary purpose of placing geotextile filter fabric between native soil and imported pea-gravel or crushed-stone tank backfill?
In excavations where a hazardous atmosphere could reasonably be expected, OSHA requires testing before workers enter when the excavation is generally how deep?
When a trench shield (trench box) is used to protect workers installing product piping, the shield must be:
A competent person is classifying soil at a tank site that was previously excavated and backfilled. How does OSHA generally treat previously disturbed soil?
OSHA allows a short-term maximum simple slope of ½ horizontal to 1 vertical in Type A soil only when the excavation is:
PEI RP100 practice for placing tank backfill emphasizes compacting or consolidating the material in lifts primarily to:
Open tank excavations that employees or the public could fall into must be:
Which PEI recommended practice is the primary industry guide for installing underground liquid storage systems, and which addresses aboveground motor-vehicle fueling systems?
Tank Installation Testing
What is a primary purpose of a pre-installation air/soap or tightness test on a new UST before backfill is completed?
NFPA 30 tightness-testing practice for single-wall underground tanks and piping, before they are covered or placed in use, commonly requires a hydrostatic test or an air test at:
Why must air pressure not be used to tightness-test a tank that already contains flammable or combustible liquid or vapor?
Corrosion protection for steel USTs commonly includes which combination?
What is the purpose of dielectric isolation (bushings or unions) in metallic UST systems that use cathodic protection?
Secondary containment for tanks is intended to:
A double-wall tank's interstitial space should be:
Federal UST overfill-prevention equipment is commonly designed so that it either automatically shuts off delivery when the tank is no more than 95 percent full or alerts the transfer operator when the tank is no more than:
A spill-containment manhole (spill bucket) at a UST fill is installed primarily to:
When hold-down straps are used to anchor a UST to a concrete deadman or pad, the straps must typically be:
A horizontal cylindrical UST has an 8 ft diameter and a 27 ft shell length. Using V = πr²L and 7.48 gallons per cubic foot, the tank's approximate geometric volume is:
An 8 ft-diameter horizontal tank is 20 ft long. What is its approximate internal volume in cubic feet? (Use V = πr²L.)
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