ASTM D3393 explained for coated fabric waterproofness in construction

What ASTM D3393 covers

ASTM D3393 is a standard specification for the waterproofness of coated fabrics. In practical procurement terms, it gives buyers, specifiers, and laboratories a recognized way to state whether a rubber- or plastic-coated fabric meets a minimum hydrostatic resistance requirement. ASTM International identifies ASTM D3393-91(2022) as the active edition, last updated on November 7, 2022.

The standard is narrow by design. It addresses liquid water passing through the coated fabric itself. It does not evaluate every possible leak path in a finished construction cover, enclosure, canopy, or temporary weather protection system.

For construction readers, the main use is straightforward: apply ASTM D3393 when the product is a coated fabric and the claim concerns waterproofness of the fabric sheet. Do not use it as a shortcut for complete assembly performance, seam quality, fastening design, drainage, wind resistance, fire behavior, or long-term weathering. For broader standard discussions, see the Realloong standards section.

The public ASTM listing describes the scope as rubber- or plastic-coated fabrics and states that fabrics satisfying the requirement are considered waterproof under the specification. It also says the standard does not cover water repellency or general water resistance. That distinction is important because product descriptions often use terms such as waterproof, water-resistant, water-repellent, rainproof, and weatherproof as if they mean the same thing. In a technical specification, they do not.

Waterproofness under ASTM D3393 is tied to hydrostatic resistance. Hydrostatic resistance is the ability of a material to resist water penetration when water pressure is applied. A coated fabric may shed spray from its surface but fail under sustained pressure. Conversely, a fabric sheet may pass a hydrostatic check while a finished item still leaks at stitched seams, heat-welded joints, zippers, eyelets, or poorly detailed edges. ASTM D3393 is therefore best read as a material-level criterion, not a full system approval.

How the hydrostatic resistance criterion works

The standard uses a hydrostatic tester capable of applying and maintaining a specified water pressure. ASTM’s public abstract also refers to specimen selection from a roll of coated fabric and to clamping equipment designed to hold the specimen without cutting it or allowing edge leakage. These details point to the purpose of the test: the procedure should challenge the coated fabric surface, not create a false failure through poor clamping or unintended leakage around the specimen.

Public summaries of older D3393 editions describe a pressure level around 207 kPa, equivalent to 30 psi, with repeated pressure application followed by a short sustained hold. The official ASTM standard remains the controlling document. Buyers should not rely on secondary summaries when writing contractual acceptance language. If the exact pressure cycle, specimen count, orientation, or reporting format matters, the project team should use the licensed ASTM text and require the laboratory to identify the edition used.

The basic concept is simple. A sample of coated fabric is held in the test apparatus. Water pressure is applied to one side. The exposed side is observed for evidence of water penetration. If water passes through the fabric during the required exposure, the material does not meet the waterproofness criterion. Because the result is tied to a defined requirement, ASTM D3393 is more useful for pass/fail procurement language than for ranking many fabrics across a broad performance scale.

The standard treats SI units as the standard units, with inch-pound units presented for information. This matters on international projects, where suppliers may quote pressure in psi while laboratories and specifications may work in kPa. Submittals can show both units for clarity, but the applicable ASTM edition should control the test requirement.

Where ASTM D3393 fits in construction applications

Coated fabrics appear in many construction-related uses, even when they are not marketed as building products. Common examples include temporary tarpaulins, construction covers, scaffold enclosure fabrics, dust and weather curtains, industrial canopies, equipment covers, containment sheets, and some site protection materials. In these applications, a purchaser may need evidence that the fabric panel itself resists water penetration before it is fabricated, installed, or exposed to jobsite damage.

This is the practical value of ASTM D3393: it gives a narrow but defensible answer to one question. Does the coated fabric meet a recognized waterproofness criterion under hydrostatic pressure? In procurement, a narrow answer can be helpful because it reduces ambiguity. A supplier can submit a laboratory report, the buyer can check the standard designation and edition, and both parties can separate fabric waterproofness from other performance issues.

For permanent building envelope components, more caution is needed. Roofing membranes, air barriers, water-resistive barriers, flashing systems, and fenestration products are usually governed by different material or assembly standards. If a product is not a rubber- or plastic-coated fabric, ASTM D3393 may be irrelevant or only indirectly informative. A construction specification should not insert ASTM D3393 simply because the project involves water control. The product type and failure mode must match the standard.

What ASTM D3393 does not prove

The most common mistake is to treat a passing ASTM D3393 result as proof that a finished product will not leak in service. The standard does not make that claim. It does not evaluate a full enclosure, seam workmanship, water flow toward a joint, ponding at low spots, capillary movement through stitching, or installation damage. It also does not prove that the same fabric will remain waterproof after months of sunlight, repeated folding, abrasion, freeze-thaw exposure, or jobsite contamination unless those conditions are separately specified and tested.

ASTM’s public description specifically separates waterproofness from water repellency and water resistance. Water repellency usually concerns surface behavior, such as whether droplets bead and roll off. Water resistance is a broader and less precise term that may refer to partial resistance under limited conditions. Waterproofness in ASTM D3393 is linked to hydrostatic resistance of coated fabric. Specifications should keep this language clear. If the project needs repellency, specify a repellency test. If it needs hydrostatic waterproofness, specify ASTM D3393. If it needs both, require both.

The standard also does not replace a project risk assessment. A temporary roof cover over stored interior materials may need much more than material waterproofness. Wind uplift, edge restraint, overlap direction, puncture from debris, slope, ponding, and daily inspection may determine whether the cover performs as intended. A scaffold enclosure used in a dense urban project may also need fire performance, visibility, attachment, and tear propagation requirements that are unrelated to ASTM D3393.

Sample representation is another limitation. A test specimen may come from a roll, but construction performance depends on consistency across production, shipping, fabrication, and installation. If a project is sensitive to water ingress, the specification should define lot traceability, whether seams are included, what happens after a failed specimen, and whether retesting is allowed. Without those details, a single pass report may not answer the buyer’s actual risk question.

ASTM D3393 compared with related waterproofness measures

ASTM D3393 is a specification for coated fabric waterproofness. ASTM D751, by contrast, is a broader collection of test methods for coated fabrics. Public ASTM information for D751 lists multiple property areas, including dimensions and mass, breaking strength, elongation, bursting strength, puncture resistance, tear tests, hydrostatic resistance, coating adhesion, low-temperature behavior, seam strength, aging, blocking, crush resistance, and wicking. The two standards can serve different roles in the same procurement package. See also: Membranes.

A simple way to separate them is this: ASTM D3393 helps define whether a coated fabric can be called waterproof under its criterion, while ASTM D751 and other methods help describe broader physical durability. A construction cover that passes waterproofness but tears easily may still be unsuitable. A fabric with strong tear performance but inadequate hydrostatic resistance may be durable but not waterproof. Both questions matter, but they are not the same question.

Hydrostatic head ratings can also cause confusion. Outdoor and textile markets often express water resistance as millimeters of water column. That approach measures the pressure created by a column of water and can be useful for comparing fabrics in some markets. ASTM D3393, however, is not simply a consumer-style millimeter rating. It is a specific coated-fabric waterproofness specification. If a supplier provides only a hydrostatic head number, the buyer should ask whether the material was tested to ASTM D3393, another named method, or an internal procedure.

For construction purchasing, avoid translating one claim into another unless the laboratory report supports it. A data sheet statement such as waterproof fabric may not be enough. A stronger submittal identifies the standard, edition, laboratory, sample description, date, result, and any deviations. If the test was modified, the modification should be stated clearly rather than left unclear in a footnote.

How to specify ASTM D3393 without overclaiming

A good specification starts with the correct material description. If the product is a rubber- or plastic-coated fabric, ASTM D3393 may be relevant. If it is an uncoated woven textile, a film, a laminated sheet, a roofing membrane, or a full building assembly, confirm the appropriate standard before inserting D3393. The standard should answer a real acceptance question, not merely add a familiar ASTM reference.

Use clear language such as: coated fabric shall meet ASTM D3393-91(2022), or the current edition if expressly accepted by the project documents, for waterproofness of the coated fabric sheet. Then add the project-specific details the standard alone may not settle: sample source, lot identification, whether coating-side orientation matters, whether seams are tested, conditioning before testing, acceptance criteria, and reporting requirements.

For higher-risk uses, consider before-and-after testing. A fabric may pass as manufactured but lose performance after UV exposure, folding, abrasion, laundering, cleaning chemicals, low-temperature flexing, or heat aging. ASTM D3393 can be part of that program if the project requires waterproofness after conditioning, but the conditioning method itself must be specified. Do not assume that a standard material test automatically includes every aging exposure relevant to the jobsite.

Submittal review should also check the age and edition of the report. ASTM D3393-91(2022) is the active edition identified by ASTM’s public record as of the latest available listing reviewed for this article. Older reports may still be informative, but the contract should state whether older editions are acceptable. If the report cites a modified procedure, the reviewer should decide whether the modification is technically acceptable before approving the material.

• Identify the coated fabric by product name, substrate, coating type, weight, thickness if available, color, and production lot.
• Require the laboratory report to state the ASTM D3393 edition and whether the method was modified.
• Separate sheet waterproofness from seams, hems, welds, stitches, penetrations, and installed overlaps.
• Add durability tests when the fabric will face wind, abrasion, UV exposure, cold folding, or repeated reuse.
• Do not convert marketing terms into compliance claims unless a test report supports the claim.

The practical takeaway is that ASTM D3393 is useful because it is limited. It creates a recognized waterproofness check for coated fabrics, but it does not answer every construction water-control question. Used carefully, it can make procurement more objective. Used loosely, it can create a false sense of assurance.

Frequently asked questions

Is ASTM D3393 the same as a water-repellency test?

No. ASTM’s public description states that D3393 addresses hydrostatic resistance for coated fabric waterproofness and does not cover water repellency or general water resistance. Water repellency concerns surface behavior; ASTM D3393 concerns water penetration through the coated fabric under pressure.

Can ASTM D3393 be used for construction tarps?

Yes, when the tarp material is a rubber- or plastic-coated fabric and the question is whether the fabric sheet meets the waterproofness criterion. The finished tarp may still need separate checks for seams, hems, grommets, tear strength, UV exposure, and installation conditions.

Does a passing ASTM D3393 result mean a canopy will never leak?

No. It supports a material-level waterproofness claim for the coated fabric. A canopy can leak through seams, joints, fasteners, low-slope areas, damaged coating, or poor drainage even if the fabric panel passes the test.

Which edition should a specification cite?

ASTM lists ASTM D3393-91(2022) as the active edition in its public record reviewed for this article. A project specification should cite the required edition or state whether the current edition at the time of testing is acceptable.

What should be requested in a test report?

Ask for the standard designation and edition, sample identification, test date, laboratory name, number of specimens, observed result, test conditions, and any deviation from the standard procedure. For construction use, also clarify whether the report applies only to flat fabric or includes seams and fabricated details.