Towel testing is the set of product and method tests that verify a terry towel's water absorbency, pile (loop) integrity, dimensional stability, colorfastness, fibre content, and safety properties meet its product standard — in China GB/T 22864 (Towels, national standard platform) with test methods in GB/T 22871 (Towels — Test methods, which consolidated the former GB/T 22799 absorbency and GB/T 22798 pile-loss standards), and internationally ASTM D4772 (surface water absorption, ASTM catalog), AATCC 79 (absorbency time) and the ISO 105 colorfastness series. It is not a re-run of general Fabric testing — a towel is judged first by what makes it a towel: how fast and how much water it picks up, and how much pile it sheds in service and after washing. Those two properties (absorbency and pile loss) are the headline tests that decide whether a terry product is fit for use, and they are what general fabric tests (weight, strength, colorfastness) cannot capture. Towel testing therefore sits alongside our broader fabric testing and Cashmere testing work — the weight, strength, and colorfastness methods are shared across textiles, but the absorbency and pile-integrity tests are towel-specific and are what a towel datasheet must report on its own.
What Makes a Towel a Distinct Test Subject?
A terry towel is a woven fabric with pile loops standing up from a ground weave (terry cloth background) — and that pile is what does the drying. The pile loop is a capillary structure: water climbs the loop by capillary action along the yarn's fibre bundle, then is held in the voids between fibres. This makes a towel's absorbency a function of three things that general fabric tests do not measure:
- Pile loop geometry — loop height and loop density (loops per unit area). A dense, tall loop presents more capillary surface and holds more water per square metre.
- Yarn type — ring-spun vs open-end vs zero-twist. Zero-twist pile yarns have very low twist so the fibre bundle opens and wicks fast; they test higher on absorbency but can shed more.
- Fibre and finish — long-staple cotton wicks and lasts; cationic softeners coat the fibre with a hydrophobic film and kill absorbency (this is the most common reason a heavy, soft-feeling towel tests badly on absorbency).
The fact the SERP obscures: GSM (grams per square metre) is a poor predictor of absorbency. A 500 GSM towel with poor yarn, low loop density, and a heavy softener finish will absorb less than a 350 GSM towel with zero-twist long-staple pile and no softener. GSM measures weight, not the capillary structure that does the drying — which is why towel testing measures absorbency directly rather than inferring it from weight.
What Are the Headline Towel Tests?
The two tests that define a terry product, and that general fabric testing does not cover:
- Water absorbency (GB/T 22871 / former GB/T 22799; ASTM D4772; AATCC 79) — measured by three distinct methods, each answering a different question:
- Capillary rise (GB/T 22871) — a strip of towel is suspended with its lower end in water; the height water climbs in a defined time (commonly ≥ 30 mm / 10 min) measures wicking speed, the capillary action that starts the drying.
- Surface water absorption / water-flow method (ASTM D4772) — water is poured onto the terry surface at a defined flow rate and time; the mass retained measures how much water the towel picks up off a surface (skin, dishes, furniture). This is the test that simulates real drying duty.
- Absorbency time (AATCC 79) — a single drop is placed on the towel surface and the time to absorb is measured in seconds; a fast absorbency time (commonly ≤ 5 s for a quality towel) is what the user perceives as "thirsty".
- These methods are not interchangeable — a towel can show good capillary rise (wicks fast) but poor surface absorption (holds little), or vice versa. A defensible towel report cites the method and the result.
- Pile loss / linting (GB/T 22871 / former GB/T 22798) — the percentage of fibre mass shed from the towel's pile under defined washing and abrasion. Pile loss is the test that decides whether a towel will lint onto the user, clog a dryer filter, or thin out after repeated laundry. The first 2–3 washes normally shed some loose surface fibre; persistent high pile loss after the initial shedding indicates weak yarn or poor loop anchorage and is a fail.
What Other Tests Complete the Towel Profile?
Beyond absorbency and pile loss, a full towel characterization includes the properties shared with woven fabrics but with towel-specific acceptance:
- Size and weight (GSM) after standard washing — verifies the towel meets its nominal dimensions and weight, with the weight deviation limited by GB/T 22864. Size is measured after a defined wash because terry fabrics relax and shrink on first laundering.
- Fibre content (FZ/T 01053 / GB/T 2910) — cotton content and any blend (polyester, bamboo viscose, microfiber) must match the label. A towel sold as "100 % cotton" that contains polyester is both a labelling violation and a performance defect (polyester pile wicks and dries differently).
- Breaking strength (GB/T 3923) — the tensile strength of the ground fabric, which carries the structural load while the pile carries the water.
- Colorfastness — soap washing (GB/T 3921), water (GB/T 5713), rubbing — wet and dry (GB/T 3920), and chlorine bleach (GB/T 7065). Chlorine bleach fastness is towel-specific: hospitality and hospital towels are laundered in chlorine bleach, and a towel that fades or stains in bleach fails the hospitality duty cycle (commonly 150–200 industrial washes).
- Dimensional stability after washing — the shrinkage on first laundering, which must stay within the standard limit.
- pH and formaldehyde (GB 18401) — safety properties, especially for towels in skin contact and for Class A infant towels (see below).
What Safety Tests Apply — and What Is Class A?
Towels are governed by GB 18401-2010 (National general safety technical code for textile products), which classifies textiles into three categories by end use:
- Class A — articles for infants under 36 months (infant towels, bibs). The strictest limits: formaldehyde ≤ 20 mg/kg, pH 4.0–7.5, no objectionable odour, colorfastness to water/perspiration/saliva ≥ 3-4, and banned aromatic amines (azo dyes, GB/T 17592) below 20 mg/kg. An infant towel must be Class A — Class B or C is non-compliant for that end use.
- Class B — products in direct skin contact (most bath towels, face towels). Formaldehyde ≤ 75 mg/kg, pH 4.0–8.5.
- Class C — products not in direct skin contact (decorative textiles). Formaldehyde ≤ 300 mg/kg, pH 4.0–9.0.
A towel sold without naming its GB 18401 class is unverifiable for safety compliance — and an infant towel that is not Class A is illegal in China regardless of how well it absorbs water. The Class A requirement is the same safety logic that governs our Infant pacifier testing — any textile or article intended for under-36-month use must meet the strictest chemical and colorfastness limits. On the pile-fabric side, the loop-integrity and shedding methods also overlap with Carpet testing, where pile wear and fibre release are measured the same way.
Frequently Asked Questions
What standard governs towel testing?
GB/T 22864 (Towels, the product standard) defines the requirements; GB/T 22871 (Towels — Test methods) defines the methods, having consolidated the former GB/T 22799 (absorbency) and GB/T 22798 (pile loss). Internationally, ASTM D4772 (surface water absorption) and AATCC 79 (absorbency time) cover the headline absorbency tests, with ISO 105 covering colorfastness. Safety is governed by GB 18401.
What is the difference between GSM and absorbency?
GSM (grams per square metre) measures the weight of the fabric; absorbency measures how much water it picks up. A heavy towel with poor yarn, low loop density, and cationic softener can test worse on absorbency than a lighter towel with zero-twist long-staple pile. GSM is reported, but absorbency is measured directly because weight does not predict the capillary action that does the drying.
Why do towels lose absorbency after fabric softener?
Cationic fabric softeners coat the cotton fibres with a thin hydrophobic (water-repellent) film of oil/wax. This film feels soft but blocks the capillary action between fibres, so water no longer climbs the pile loop. A towel treated with cationic softener can fail the absorbency test while feeling softer — which is why industrial laundering of hospitality towels avoids cationic softeners or uses reactive (non-cationic) alternatives.
What is pile loss and why does it matter?
Pile loss (GB/T 22871 / former GB/T 22798) is the percentage of fibre mass shed from the pile under defined washing and abrasion. It decides whether a towel will lint onto the user, clog dryer filters, or thin out after laundry. The first 2–3 washes shed some loose surface fibre normally; persistent high pile loss after that indicates weak yarn or poor loop anchorage.
What is GB 18401 Class A?
Class A is the GB 18401 category for infant textile products (under 36 months) — the strictest safety limits: formaldehyde ≤ 20 mg/kg, pH 4.0–7.5, banned aromatic amines below 20 mg/kg, no odour. An infant towel must be Class A; a Class B or C towel cannot legally be sold for infant use.
How many industrial washes should a hospitality towel survive?
A professional-grade hospitality towel is expected to withstand roughly 150–200 industrial laundry cycles before its absorbency or pile integrity drops below acceptable limits. Chlorine-bleach colorfastness and pile-loss-after-washing are the tests that predict this service life — a towel that fades or sheds in bleach will fail early in a hotel or hospital laundry.
Our Testing Capabilities
Beijing ZKGX Research (ISO/IEC 17025 testing laboratory) provides towel testing across absorbency, pile integrity, physical properties, colorfastness, and safety:
- Water absorbency to GB/T 22871 / former GB/T 22799 — capillary rise, water-absorption capacity; and to ASTM D4772 (surface water absorption, water-flow method) and AATCC 79 (absorbency time) for export and hospitality qualification.
- Pile loss / linting to GB/T 22871 / former GB/T 22798 — fibre mass shed under defined washing and abrasion.
- Size, weight (GSM), weight deviation, and dimensional stability after washing to GB/T 22864.
- Fibre content to FZ/T 01053 / GB/T 2910 (cotton content and blends).
- Breaking strength to GB/T 3923; colorfastness — soap washing (GB/T 3921), water (GB/T 5713), rubbing wet/dry (GB/T 3920), chlorine bleach (GB/T 7065).
- Safety to GB 18401 — formaldehyde, pH, odour, banned aromatic amines (GB/T 17592); Class A infant towel qualification.
If you have a towel line to qualify against GB/T 22864, a hospitality specification to verify (absorbency, pile loss, bleach fastness), or an infant-towel Class A claim to test, contact our testing team to scope the applicable tests and the acceptance criteria.