AATCC 22 grades surface beading on breathable C6 fabrics; ISO 811 measures water column pressure on coated or laminated waterproof goods.
AATCC 22 Spray Test vs ISO 811 Hydrostatic Head
The spray test (AATCC 22 / ISO 4920) grades surface water-repellent beading from 0 to 100, while hydrostatic head (ISO 811 / AATCC 127) measures waterproof pressure in mm H₂O.
Weaverine applies C6 water, oil, and soil-repellent finishes to 100% polyester upholstery, drapery, and shell fabrics across 150–315 cm finished widths (5,000 m MOQ), engineered to hold spray ratings through 30+ wash cycles.
By Wren Thunderborn, Head of Content
AATCC 22 (ISO 4920) Spray Test and ISO 811 (AATCC 127) Hydrostatic Head are the two laboratory methods that separate water-repellent fabrics from waterproof fabrics on a purchase order. Mixing the two on a tech pack is the most common reason an upholstery or outdoor shell sample fails lab testing.
1. Spray Test vs. Hydrostatic Head: Which Test Matches Which Finish?
| Parameter | Spray Test (AATCC 22 / ISO 4920) | Hydrostatic Head (ISO 811 / AATCC 127) |
|---|---|---|
| What It Measures | Surface wetting and droplet beading when 250 mL of water hits the cloth at a 45° angle from 150 mm height | Water column pressure required to force 3 drops through the thickness of the fabric |
| Reporting Unit | Photographic rating 0–100 (AATCC 22) or ISO 1–5 (ISO 4920) | Millimetres of water column (mm H₂O) or mbar |
| Target Finish Route | Breathable C6 stain- & water-repellent (三防) upholstery, tablecloths, drapery, and unlaminated pongee | PU/PA coated canopies, laminated mattress protectors, rainwear shells, and tenting |
| Air Permeability | Preserves natural weave breathability and soft hand feel | Coating or membrane blocks air and water pores |
2. AATCC 22 / ISO 4920 Spray Rating Scale (0 to 100)
During the spray test, the lab pours 250 mL of distilled water (27 ± 1 °C) through a calibrated 19-hole nozzle over 25–30 seconds onto a taut specimen inclined at 45°, taps the hoop once, and compares the face against the photographic standard chart:
AATCC 22 Score | ISO 4920 Grade | Visual Observation on Fabric Face | Typical Commercial B2B Interpretation |
|---|---|---|---|
100 | ISO 5 | No sticking or wetting of the upper surface | Initial unwashed target for high-density C6 filament weaves |
90 | ISO 4 | Slight random sticking or wetting of the upper surface | Standard commercial pass for unwashed C6 upholstery (0 washes) |
80 | ISO 3 | Wetting of upper surface at spray points | Standard pass benchmark after 10–20 domestic laundry cycles |
70 | ISO 2 | Partial wetting of the whole upper surface | Typical retention benchmark after 20–30+ commercial/home washes |
50 | ISO 1 | Complete wetting of the whole upper surface | Below commercial water-repellent threshold |
0 | ISO 0 | Complete wetting of both upper and lower surfaces | Untreated hydrophilic cloth |
3. Pairing Water Repellency (AATCC 22) with Oil Repellency (AATCC 118)
On Weaverine C6 stain-resistant (三防) programs, water repellency is only one third of the specification. A complete three-proof contract upholstery or table-linen RFQ pairs:
- Water Repellency (
AATCC 22/ISO 4920):≥ 90initial,≥ 70–80after20–30washes (ISO 6330). - Oil Repellency (
AATCC 118/ISO 14419): Graded1 to 8using hydrocarbon drops of decreasing surface tension. Standard C6 contract upholstery targets Grade4–5initial (Note: C0 fluorine-free finishes repel water underAATCC 22but score0onAATCC 118oil repellency). - Hydrostatic Head (
ISO 811): Only specify anISO 811target (≥ 1,000 mmto5,000 mm H₂O) when your order includes a back-coating or TPU lamination—never on an uncoated breathable weave.
What to Put on the Purchase Order
- Name the exact standard and wash cycle count: e.g.,
AATCC 22 ≥ 90 initial / ≥ 70 after 30 washes (ISO 6330 40 °C). - State C6 (water + oil + soil) vs. C0 (water only) chemistry based on your market's PFAS rules and oil-stain requirements.
- Specify base GSM and cuttable width (
150–280 cmfinished on functional routes,5,000 mMOQ).
Common questions
What is the difference between the AATCC 22 spray test and the ISO 811 hydrostatic head test?
- AATCC 22 (and ISO 4920) pours 250 mL of water onto a fabric at a 45° angle to grade surface beading on a 0–100 scale (ISO 1–5)—used for breathable C6 water-repellent upholstery and drapery. ISO 811 (and AATCC 127) presses a rising column of water against the cloth until three drops penetrate, measuring true waterproof pressure in millimetres of water (mm H₂O).
What do AATCC 22 spray ratings of 90, 80, and 70 mean?
- 100 (ISO 5) means no sticking or wetting of the upper surface; 90 (ISO 4) means slight random sticking; 80 (ISO 3) means wetting of the specimen face at spray points; and 70 (ISO 2) means partial wetting of the whole upper face.
Can an uncoated C6 water-repellent woven polyester pass a high hydrostatic head test?
- No. A fluorocarbon (C6) or fluorine-free (C0) DWR finish lowers surface tension so liquid beads and rolls off while keeping the weave breathable. Because the pores between warp and weft remain open, pressurized water under ISO 811 pushes through at 150–400 mm H₂O unless a PU/acrylic coating or TPU membrane is applied.
How should C6 wash durability be written on a purchase order?
- State both the initial spray rating and the rating after a defined number of ISO 6330 washes—for example: 'AATCC 22 ≥ 90 initial, ≥ 80 after 20 washes (or ≥ 70 after 30 washes), plus AATCC 118 oil repellency ≥ Grade 4.'
Related Terms
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