CHSE Odisha VOC-ITV Construction Painter & Decorator flashcards

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

Flash point

The lowest temperature at which a liquid gives off enough vapour to ignite when a flame is applied. Thinners with a flash point below 23 degrees C are classed as highly flammable.

Ladder 4 to 1 rule

The ladder base is set out one-quarter of the working height from the wall, giving roughly a 75-degree angle. The top must be secured and three points of contact kept.

Organic vapour cartridge

Respirator filter that absorbs solvent vapours from oil paints, thinners and two-pack products. It does not filter dust or isocyanate particles, which need a particulate filter.

Confined space painting hazard

Solvent vapours are heavier than air and accumulate in tanks, pits and sumps, displacing oxygen. Forced ventilation, gas testing and a standby observer outside are required.

Natural versus synthetic bristle

Natural bristle suits oil and solvent-borne paints because it holds and releases them well. Synthetic filament suits water-borne emulsion because it does not swell or soften.

Roller nap selection

Nap is the pile length of the roller sleeve. Use 4-6 mm on smooth plaster, 10-12 mm on light texture and 18-25 mm on rough masonry or render.

Airless spray tip wear

The tip orifice enlarges with use, so the spray pattern develops tails and the coating is applied unevenly. Replace the tip when the fan pattern cannot be corrected.

Brush cleaning by coating type

Water cleans acrylic and emulsion; white spirit or turpentine cleans oil and alkyd; two-pack epoxy and polyurethane need their specified thinner and must be cleaned before pot life ends.

Moisture meter reading

Instrument reading of moisture in plaster or wood. Readings above about 12-15 percent mean the substrate is not ready and coating now risks blistering and poor adhesion.

Alkali resistance test

A phenolphthalein solution turns pink on new plaster containing free alkali. Where it turns pink, an alkali-resisting primer is applied before the finish coats.

Knotting

A shellac-based sealer brushed over resinous knots in softwood before priming. It stops resin bleeding through and staining the finished paint film.

Feathering a paint edge

Sanding the broken edge of old flaking paint to a thin taper so the repair blends. Unfeathered edges show as a ridge under a gloss finish.

Efflorescence

White salt crystals brought to the surface of masonry by moisture movement. Dry-brush off the salts and remove the water source; painting over damp masonry traps moisture.

Paint components

Binder, pigment, carrier and additives. The binder or resin determines the coating family, adhesion, durability and sheen, and gives the product its generic name.

Alkyd versus emulsion drying

Emulsion dries by water evaporation and coalescence and stays permeable. Alkyd cures by oxidation, needs ventilation and yellows in dark interior conditions.

Primer, undercoat, finish

Three distinct functions: primer bonds and seals the substrate, undercoat builds opacity and fills, finish provides colour, sheen and weather resistance. They are not interchangeable.

Pot life

The usable working time after a two-pack coating is mixed. Material left beyond pot life gels and must be discarded, not thinned back into use.

Spreading rate

The area a litre covers per coat at a stated film thickness, given on the product data sheet. Rough or porous surfaces reduce the actual rate achieved.

Wet edge

The still-wet boundary of the last applied paint. New paint is worked back into it before it sets, which prevents lap marks and visible joints in the finish.

Sagging and runs

Downward flow of an over-thick or over-thinned coat. The defect is corrected only after full hardening, by sanding flat, dusting off and recoating thinly.

Spray overlap

Each spray pass overlaps the previous one by about half its width, with the gun held perpendicular at a constant distance, so the film builds evenly without bands.

Recoat window

The period stated on the data sheet during which the next coat bonds properly. Too early traps solvent and wrinkles; too late needs abrading for adhesion.

Wallpaper soak time

The wait after pasting and folding a paper before hanging, allowing it to expand fully. Hanging too soon causes bubbles and open seams as the paper expands on the wall.

Half-drop pattern match

Alternate drops are shifted by half the vertical repeat. It wastes more paper than a straight match, so extra rolls are calculated before ordering.

Rag rolling

A decorative glaze technique in which a rolled cloth is pressed and lifted over a wet glaze to produce a broken, mottled texture. It is sealed with a clear coat.

Wall area deduction rule

Openings larger than about 2 square metres are deducted from measured wall area; smaller openings are not, because their surrounds still need cutting in.

Paint quantity formula

Litres needed equals area in square metres divided by spreading rate in square metres per litre, multiplied by the number of coats. Round up to the pack size.

Break-even quantity

Fixed costs divided by the difference between unit price and unit variable cost. Selling below this volume means the business operates at a loss.

Retention money

A percentage, commonly 5-10, deducted from each bill and released after the defect liability period. It must be allowed for in the contractor's cash flow.

Drawing scale 1:50

One unit on the drawing represents 50 units on site. A 100 mm wall measures 2 mm on the drawing, and a scale bar allows checking after resizing.

Finish schedule

A table keyed to room numbers listing the coating specification for each surface. The painter takes the product and colour from it, not from the drawing.

Defect liability period

The agreed period after handover during which the contractor rectifies reported defects at its own cost. It is the reason retention is held back.