Moisture Performance / Drying / Test Method
How Is Drying Rate Measured in Knitted Fabric?
Drying rate describes water loss under a defined procedure. It is meaningful only when the applied moisture, atmosphere, airflow or heat input, specimen state, and endpoint remain attached to the result.
Drying rate is measured by applying a known quantity of water, or bringing a specimen to a defined absorbent capacity, then exposing it to controlled temperature, humidity, airflow, or surface contact while water loss is tracked over time. Depending on the method, the instrument records residual mass, percentage dried, a thermal response, or time to a defined endpoint. The report must identify the method, water load, specimen dimensions and orientation, conditioning atmosphere, exposure conditions, endpoint, units, pretreatment, and replicate data. A result without those conditions cannot support a reliable comparison.
Drying rate and drying time describe different parts of the curve
Drying is not a single instantaneous property. A wetted fabric normally passes through a changing sequence: liquid spreads through accessible capillaries, water held at the surface begins to evaporate, the evaporation front changes as the specimen loses moisture, and more strongly retained water leaves later. A method samples this sequence under defined conditions. It does not create an absolute speed that follows the textile into every climate, garment layer, or wearing situation.
ISO 17617:2014, confirmed as current in 2025, defines drying rate as the time-related drying behaviour of a fabric wetted with a known mass of water and expresses it as percentage drying per unit time. It distinguishes this from drying time, the time at which 100 percent of the applied water has dried under the procedure. The standard includes horizontal drying approaches based on residual water mass and a linear approximation of part of the drying curve. Rate and time may move in the same direction, but they are not interchangeable labels.
The phrase quick dry is therefore incomplete unless a test procedure and acceptance criterion are stated. One report may describe percentage water loss per minute after a fixed dose. Another may describe minutes to an endpoint after saturation. A third may follow heat flow from a wet specimen on a plate. Those results answer related but different questions. The lowest time or highest rate is useful only inside a compatible method.
The method defines the claim
Water quantity, specimen state, temperature, humidity, airflow, contact condition, and endpoint all shape a drying result. Matching units do not make unmatched procedures equivalent.
Different procedures simulate different drying conditions
ISO 17617 applies to textile fabrics rather than loose fibre or yarn. A known water mass is applied, the specimen is held in the prescribed horizontal arrangement, and residual water is followed through time. Because the initial dose is known, percentage drying and drying time can be calculated without confusing water uptake capacity with evaporation. The method is appropriate when a controlled fabric comparison is required, but the exact procedure and atmosphere still have to appear in the report.
ISO 13029:2012 uses a modified sweating guarded-hotplate method for dynamic drying of fabrics used in sportswear, leisurewear, underwear, and comparable next-to-skin applications. It is not intended for vapour-impermeable materials or specimens thicker than 5 mm. The plate-based thermal response makes it a different measurement from a simple mass-loss test. Its result should not be converted informally into an ISO 17617 or moisture-analyser value.
AATCC TM199 uses a gravimetric moisture analyser at elevated temperature for knit, woven, and nonwoven fabrics. The method also allows nonstandard temperatures when a laboratory needs to simulate a selected body or use condition, but any departure must remain explicit. AATCC TM200 evaluates drying at absorbent capacity under airflow and excludes socks and hosiery from its stated scope. AATCC TM201 applies a prescribed water volume and follows drying on a plate maintained at 37 degrees Celsius. These options demonstrate why the intended question should be selected before a target is written.
Whichever procedure is chosen, specimens require representative sampling and conditioning. ISO 139 establishes standard atmospheres for textile conditioning and testing. A knit taken directly from the machine, a steamed approval panel, and a washed production sample can have different dimensions, thickness, finish distribution, and moisture regain. Testing them under one heading without recording state conceals rather than controls the variation.
Initial water, liquid distribution, and construction govern the curve
Drying starts with how much water is present and where it sits. A hygroscopic fibre can hold moisture within its structure; a low-absorbency filament may retain less internally while a textured yarn traps liquid between filaments and loops. Finishes can increase or suppress wetting, and capillary pathways can distribute a dose over a larger area. Wicking can support evaporation by spreading water, but fast spreading does not guarantee fast drying if the fabric also retains a large water mass.
Loop architecture determines thickness, exposed surface, pore continuity, and contact between wet regions. Single jersey, rib, interlock, tuck structures, transferred lace, plated constructions, and engineered zones do not present the same evaporation geometry. The relationship between courses and wales can make liquid distribution directional. Pile, brushing, floats, and bulky relief may increase surface area while also creating reservoirs that prolong the later stage of drying.
GSM is useful production information, but lower mass does not automatically mean a faster result. Two fabrics at similar mass can differ in thickness, density, fibre regain, yarn bulk, finish, and the amount of water applied by the selected method. If one procedure doses by area and another begins at absorbent capacity, a light fabric may start with far less water in the first comparison and a materially different load in the second.
Yarn count, twist, filament shape, texturing, hairiness, and ply alter capillary channels and exposed area. Stitch length, take-down, machine gauge, and finishing set the final loop dimensions. Relaxation and washing can compact a structure, remove processing auxiliaries, redistribute a hydrophilic finish, or change thickness. The approved care state should therefore be part of the sampling plan rather than an afterthought.
Environmental variables remain equally important. Warmer air can increase evaporation potential; greater air movement can remove the humid boundary layer; relative humidity changes the vapour-pressure gradient; contact with a plate can supply heat differently from free airflow. Mounting can expose one or two faces and can either preserve or suppress dimensional curl. These are controlled parts of the test, not laboratory background.
A useful approval connects the number to end use
The test should reflect the decision being made. A next-to-skin knitted layer may need evidence from a plate-based procedure, while a lightweight outer layer may be compared through controlled mass loss or airflow. A garment with dense ribs, mesh panels, plated zones, or integral trims may require a mapped sampling plan. Averaging unlike zones into one figure can erase the exact area that needs adjustment.
Development comparisons should isolate variables. Hold yarn, colour, and finish constant while changing stitch architecture; then hold the selected structure while evaluating yarn or finish. Record individual results as well as mean and variability. If wetting is visibly uneven, document it rather than forcing a smooth interpretation. A laboratory report should include standard and edition, apparatus or procedure, water application, specimen dimensions, face and orientation, atmosphere, temperature, humidity, airflow or plate condition, preconditioning, care state, endpoint, units, and number of determinations.
Drying data should also be read alongside air permeability and thermal and water-vapour resistance. Pressure-driven airflow, evaporation of liquid water, dry heat flow, and vapour transfer are separate mechanisms. A complete comfort brief may need several measurements, not one broad claim.
The development process translates the selected evidence into yarn, stitch, finish, care, and factory-control decisions. Relevant construction studies appear in Work. Anne's technical scope is described in About; material-specific enquiries can be submitted through the contact form.
Common questions about drying rate
What does quick drying mean for a knitted fabric?
It should mean that the fabric reaches a defined drying rate or time under a named test. Without water load, atmosphere, exposure condition, endpoint, and units, “quick drying” is descriptive language rather than a comparable specification.
What is the difference between drying rate and drying time?
Drying rate describes water loss over an interval, often as percentage per unit time. Drying time is the duration required to reach the method's endpoint, such as complete loss of the applied water.
Is drying rate the same as wicking?
No. Wicking measures liquid movement through or across a textile. Drying measures water loss from it. Spreading may increase the evaporating area, but retained water and environmental conditions still control the drying curve.
Does a lower-GSM knit always dry faster?
No. Fabric mass is only one variable. Fibre regain, thickness, loop geometry, finish, pore structure, exposed area, and the test's initial water condition can change the result.
Do synthetic fibres always dry faster than natural fibres?
No universal result follows from fibre name alone. Internal absorption can differ, but yarn construction, texturing, fabric structure, finishes, retained water, and test conditions remain decisive.
Can results from different drying methods be compared?
Not directly unless a validated correlation exists for the specific materials and conditions. A moisture analyser, airflow method, horizontal mass-loss method, and heated-plate method impose different inputs and endpoints.
Should drying be tested after washing?
Yes when the approval concerns the cared product. Washing can remove auxiliaries, change hydrophilic finishes, relax loops, and alter thickness. Initial and cared states may both be necessary.
Drying performance is a controlled relationship, not a fibre slogan
A defensible drying statement keeps the water load, fabric state, environment, and method visible. Once those controls are fixed, the result can identify whether fibre system, yarn, loop architecture, or finishing needs adjustment. Without them, apparent speed may reflect only a different starting condition.