IICRC RCT key terms

The two yarn systems that form a rug's foundation: warp yarns run lengthwise under tension on the loom, while weft yarns run crosswise and are interwoven with them. Both affect stability, drape, and how a rug reacts to moisture.

The short length of yarn tied around warp yarns to create the upright surface of a hand-knotted rug. Knot type and density determine pattern detail, durability, and the rug's value.

A measure of knot density expressed as knots per square inch. Higher counts generally mean finer detail and a more valuable rug, but they also mean tighter construction that resists soil removal and drying airflow.

A rug built by tying individual pile knots onto a loom-woven foundation. Because dyes, fibers, and tensions vary, hand-knotted rugs demand cautious testing and controlled moisture rather than uniform production-line cleaning.

A rug made by shooting yarn through a primary backing with a tufting gun, then securing it with a secondary backing and adhesive. Latex and glue layers can fail or bleed if the rug is over-wetted.

The structural grid of warp and weft yarns, plus any backing, that supports the pile. Foundation fiber type and condition govern how much weight, agitation, and moisture a rug can safely tolerate.

A protein fiber from sheep, the most common pile material in hand-made rugs. Wool accepts acid dyes, holds soil in its scales, and can shrink or felt with heat, friction, and excess water.

A fine protein filament fiber used in high-end pile and highlights. Silk is strong dry but weak when wet, sensitive to alkaline products, and prone to watermarking and color bleed, so it needs low-moisture methods.

Plant-derived fibers such as cotton, jute, sisal, linen, and rayon/viscose. They absorb water readily, are sensitive to acids and high alkalinity, and can brown, shrink, or split at seams when over-wetted.

A coarse cellulosic fiber used in foundations, backing, and flatweaves. Jute stains brown and weakens quickly when wet, so it is a key reason to control moisture and dry rugs face-down or with airflow beneath.

The way light reflects from a fiber surface, influenced by fiber type, twist, and wear direction. Changes in luster after cleaning can signal abrasion, product residue, or pile distortion and should be noted in pre-inspection.

Intentional or incidental color variation in a rug, common in tribal weaving where dye lots changed. It is a normal characteristic, not a stain or cleaning defect, and must be documented before work begins.

A rug with no pile, woven by interlacing warp and weft, such as kilim, dhurrie, or soumak. Without pile to protect the foundation, flatweaves show wear fast and are prone to shrinkage and dye transfer.

A pileless tapestry-woven rug, usually wool, with slits where color blocks meet. Slits, weak selvedges, and fugitive dyes make kilims candidates for low-moisture cleaning and careful handling.

A broad trade category for hand-made rugs of Middle Eastern, Central Asian, or Asian design origin. The term describes style and construction tradition, not a single fiber or cleaning method.

The systematic examination of a rug before cleaning to identify fiber, construction, condition, existing damage, and colorfastness. Findings are documented and discussed with the client to set expectations and limit liability.

A written and photographic record of a rug's size, fiber, construction, damage, stains, and pre-existing defects. Signed or acknowledged by the client, it protects both parties if disputes arise after cleaning.

A small, inconspicuous test of each color with a damp white cloth or cotton swab to see whether dye transfers. Bleeding colors require reduced moisture, lower pH, faster drying, or refusal of wet cleaning.

Migration of dye from one area of a rug into adjacent lighter fibers, usually during wet cleaning or slow drying. Once transferred, dye is difficult to correct and may require professional reduction or color correction.

Transfer of dye from a rug onto another surface by rubbing or contact, often seen on a client's floor or furniture. It indicates loose or unstable dye and calls for testing and cautious handling.

A brownish discoloration on cellulosic fibers caused by moisture wicking natural compounds to the surface or by over-wetting and slow drying. Correct drying and acid rinsing help prevent or reduce it.

Irreversible matting and tightening of wool fibers caused by heat, moisture, and friction. It shrinks pile and distorts pattern, so agitation must be minimized on wool rugs.

The likelihood that cotton, jute, or viscose areas will discolor or weaken from moisture. Assess it during pre-inspection and plan faster drying, lower moisture, and airflow under the rug.

Categorizing soil as soluble, insoluble, oily, or bonded to the fiber so the correct chemistry and agitation can be selected. Correct classification prevents over-wetting and ineffective cleaning.

A cleaning agent molecule with a water-loving head and oil-loving tail that lifts and suspends soil in solution. Concentration, pH, temperature, and dwell time determine how well it works and how safely it rinses out.

A measure of acidity or alkalinity on a 0-14 scale. It affects dye stability, fiber damage, and soil removal; wool and silk prefer mild acidity, while cellulosics are harmed by strong acids or alkalis.

A dilute acid solution applied after cleaning to neutralize alkaline residue and lower pH. It helps restore wool's hand, reduces browning risk, and limits dye migration during drying.

The state in which loosened soil is held in the cleaning solution rather than redepositing on the fiber. Adequate flow, dwell time, and extraction keep soil suspended until it is removed.

Removing cleaning solution, suspended soil, and moisture from a rug using vacuum, wand, or compression. Thorough extraction shortens drying time and reduces browning, shrinkage, and wicking.

Upward movement of moisture and dissolved soil through a rug as it dries, leaving rings or reappearing stains. Fast, even drying and controlled moisture prevent it.

Bending, matting, or crushing of pile from wear, furniture, or aggressive agitation. Some distortion is permanent; cleaning should avoid worsening it and finishing may improve appearance.

Finishing work that lifts and aligns pile with brushes or combs after drying. It improves appearance and luster but must be done gently to avoid felting or stretching the foundation.

Weakening and crumbling of foundation fibers from prolonged moisture exposure, often from urine or over-wetting. It cannot be restored by cleaning and must be documented and referred for repair.

Penetration of urine into pile and foundation, leaving salts, odor, and possible fiber damage. It requires specialty treatment, controlled moisture, and sometimes sub-surface flushing rather than routine cleaning.

Reducing or neutralizing smells through source removal, cleaning, and appropriate products rather than masking. Success depends on reaching the contamination layer and fully drying the rug.

Controlled removal of moisture using airflow, temperature, and time while maintaining shape. Rugs should dry flat or face-down with air beneath, away from direct sun and heat, to limit bleed and shrinkage.

A documented record of who handled a rug at each stage, from pickup through cleaning and delivery. It supports accountability and helps resolve claims about loss or damage.

Gloves, eye protection, respirators, and footwear worn to reduce exposure to chemicals, dust, mold, and biological contamination. Selection depends on the products and conditions of each job.

A standardized document listing a product's hazards, handling, first aid, and storage requirements. It must be accessible on site and reviewed before using unfamiliar chemicals.