Red Seal HEO flashcards

34 cards. Read the term and the definition here. The deck at the top of this page is optional.

Competent person (excavation)

A person capable of identifying existing and predictable hazards in the surroundings or working conditions and who has authority to take prompt corrective measures to eliminate them, including daily trench inspections.

Tolerance zone

The band measured horizontally from each side of a buried utility, commonly 1 m or 3 ft, within which excavation must be done by hand or non-destructive methods rather than mechanical digging.

Hierarchy of controls

The ranked order of hazard controls from most to least effective: elimination, substitution, engineering controls, administrative controls, and personal protective equipment last.

Type C soil

Cohesive soil with unconfined compressive strength of 0.5 tons per square foot or less, or any granular, submerged, or previously disturbed soil, requiring the most protective trench system.

Swing radius control

The practice of keeping the bucket or load low and close to the machine while swinging, and never swinging a load over personnel, trenches, or another machine's cab.

Track idler orientation

Tracked excavators normally travel with the idler forward and the drive sprocket trailing, which improves stability and climbing ability on grades and soft ground.

Slot dozing

A dozing technique where parallel trenches are cut so material spills into adjacent slots, reducing rolling resistance and side spill, which increases production over straight pushing.

Loader bucket fill factor

The ratio of actual bucket volume to rated capacity, improved by a level floor, a low approach speed, and a breakout curl that rolls material into the bucket at the pile.

Articulation point hazard

On a wheel loader the rear frame swings outside the front frame path during turns; the tail swing must be checked before turning near walls, banks, or people.

Swell factor

The increase in volume when bank material is excavated and loosened, expressed as a percentage; loose volume equals bank volume multiplied by one plus the swell fraction.

Optimum moisture content

The moisture level at which a soil reaches its maximum dry density under a given compactive effort; density falls off if the soil is too dry or too wet.

Lift thickness

The loose depth of a soil layer placed before compaction, typically 150 to 300 mm for a smooth-drum roller; thicker lifts leave loose material at the bottom of the layer.

Cut and fill balance

A grading plan where total cut volume equals total fill volume adjusted for swell and shrinkage, minimizing haul distance, borrowed material, and wasted material off site.

Batter board

A horizontal board set on stakes outside the excavation line at a known elevation, used with a string line to control grade, depth, and alignment during excavation.

Track tension check

Measure sag at the midpoint between the idler and first carrier roller with the machine on level ground; typical specification is roughly 10 to 20 mm of sag.

Hydraulic oil contamination signs

Milky or foamy hydraulic oil indicates water or air ingress; both reduce lubricity and can damage pumps and valves, so the cause must be found before continued operation.

Hour-meter maintenance interval

Preventive maintenance schedules are keyed to accumulated operating hours recorded on the hour meter, not calendar time, and the readings must be logged at each service.

ROPS and FOPS

Roll-over protective structure and falling-object protective structure; cracked, bent, or modified structures void protection and must be repaired by qualified personnel before use.

Utility color code

Standard marking colors: red for electric, yellow for gas and oil, orange for communications, blue for potable water, green for sewer, purple for reclaimed water, white for proposed excavation.

Benchmark

A fixed point of known elevation or coordinates used as the reference for surveying and grading; a temporary benchmark on site is tied to a permanent datum.

Station and offset

A surveying notation where stationing measures distance along a baseline in 100-unit stations and offset gives the perpendicular distance left or right of that baseline.

Silt fence placement

A sediment barrier installed downslope of disturbed ground before clearing begins, keyed into the soil, and maintained until the area is stabilized with vegetation or cover.

Sling angle factor

A multiplier applied to the load per leg as the sling angle from horizontal decreases: about 2.0 at 30 degrees, 1.4 at 45 degrees, and 1.15 at 60 degrees.

Working load limit

The maximum load a rigging component or assembly may safely handle in a specified service; the assembly limit is set by its weakest component.

Excavator lifting requirements

Lifting with an excavator requires a load chart for lifting, a certified lifting point, and hose-burst check valves on the boom and stick cylinders.

Quick coupler verification

Before digging or lifting, confirm the attachment is fully seated in the coupler and the locking pin or wedge is installed and visually checked by the operator.

Aggregate tiedown strength

The combined working load limit of all tiedowns securing an article must be at least 50 percent of the weight of that article, and each tiedown must be rated and marked.

Tiedown count rule

At least one tiedown per 3 m of article length, with a minimum of two tiedowns for any article longer than 1.5 m or heavier than 500 kg.

Transport position

The manufacturer-specified configuration for moving a machine, typically attachment lowered and pinned, parking brake set, and transmission or controls locked out.

Radio and hand signal protocol

One designated signal person directs the operator; radio messages identify the machine and are confirmed on receipt, and anyone may give an emergency stop signal.

Field-level hazard assessment

A documented pre-job review of tasks, hazards, controls, and participants completed before work begins and updated whenever site conditions or the scope of work changes.

Diesel no-start sequence

Troubleshooting order for a diesel that will not start: battery and connections, fuel supply and filter restriction, air in the fuel system, then compression and injection timing.

Exhaust smoke diagnosis

Black smoke indicates incomplete combustion from over-fueling or air restriction, blue smoke indicates oil burning, and white smoke indicates unburned fuel or coolant entering the cylinder.

Cylinder drift diagnosis

An attachment that drifts down under load usually has internal leakage past the piston seal or a faulty holding valve, rather than a failed hydraulic pump.