IPX7 vs IPX8: Which Rating Belongs in Your Tech Pack

Two Digits, Two Very Different Promises

The IP code is defined by IEC 60529, which splits protection into two numerals: the first for solid objects, the second for water. An X in the first position means the solid-ingress characteristic was not tested or not declared, not that it is zero. So IPX7 and IPX8 are both statements about water only, and both are produced by a laboratory immersion test rather than by a calculation based on fabric data.

The critical difference is that IPX7 is a fixed prescription and IPX8 is a negotiated one. IEC 60529 sets the IPX7 condition in the standard itself, so every lab runs essentially the same test. For IPX8 the standard requires conditions more severe than IPX7, but the actual depth and duration are agreed between the manufacturer and the purchaser. That makes two IPX8 certificates from two suppliers impossible to compare unless both print their numbers.

Buyers routinely assume that IPX8 is simply better than IPX7 in every respect. It is not. An IPX8 claim tested at 1.5 m for 30 minutes is marginally above IPX7 and gives you nothing extra in the field. An IPX8 claim tested at 3 m for 60 minutes is a different product entirely. The rating label is identical in both cases, which is exactly why procurement teams should never accept a bare IPX8 on a specification sheet.

There is also a scope issue that is easy to miss. IEC 60529 was written around enclosures for electrical equipment, which are rigid, sealed and fixed in shape. A dry bag is none of those things: it folds, the roll-top creeps under pressure, and the contents change the geometry during the test. Our waterproof test and inspection protocol pairs the immersion test with a hydrostatic head figure and a seam peel figure, because the immersion test alone returns a single pass or fail for one artificial configuration.

• IPX7: condition fixed by the standard, so it is comparable across suppliers without negotiation.
• IPX8: condition chosen by the maker, so the certificate is only meaningful when depth and duration are printed.
• Both ratings describe water ingress only; neither one addresses abrasion, UV aging or low-temperature cracking.
• Neither rating says anything about what happens after a season of use, which is where most field complaints start.

The decision rule we give buyers is simple. Choose IPX7 when the realistic failure you are protecting against is a bag falling off a boat deck, a raft flip, or a kayak roll, all of which are shallow and short. Choose IPX8 when you have a genuine deep-and-long use case, such as a dive-support bag or a product you intend to sell with an explicit depth claim. If you cannot name the depth, you probably do not need IPX8, and paying for it will not make the product better.

What the IPX7 Test Actually Does

The fixed immersion condition

Under IEC 60529 the IPX7 test immerses the specimen for 30 minutes. The standard positions the enclosure so that its lowest point sits roughly 1 000 mm below the water surface and its highest point is at least 150 mm below the surface, which keeps the whole article submerged rather than floating with a dry crown. The water is fresh, and the standard asks that the temperature of the water and of the specimen be close, so a bag pulled straight from a hot warehouse does not produce a misleading pressure reading.

Thirty minutes is longer than most real accidents, and that is the point: the test is a margin, not a simulation. What it does not cover is repetition. A bag that passes once and then dries with salt or sand in the roll-top may leak on the second dunk, because grit in the fold holds the closure open. If your product will be dunked daily, specify cycling: pass the test, dry for 24 hours, then repeat for a defined number of cycles, and inspect the closure area between cycles.

Because IEC 60529 was drafted for electrical enclosures, its pass criterion is framed around harmful ingress affecting equipment operation. That wording is useless for a soft good. You must write your own pass criterion into the tech pack. We recommend a measurable one: place a weighed indicator tissue inside the bag before the test and require zero mass gain, or require no visible moisture on an internal indicator card after the full 30 minutes. A visual-only criterion is subjective and will be argued over at the pre-shipment inspection.

Sample size is another gap. IEC 60529 does not fix a production-lot sampling plan, so the lab report tells you about the three units on the bench and nothing about the 5 000 units on the pallet. Bridge that gap with AQL 2.5 lot acceptance under ISO 2859-1, plus a defined per-lot water-test pull. On our production lines we run a daily immersion pull per style so the weld parameters stay where the qualified samples were.

What the IPX8 Test Requires the Maker to Declare

IPX8 is defined by IEC 60529 as continuous immersion in water under conditions agreed between the manufacturer and the user, and the standard states those conditions must be more severe than the IPX7 condition. That single sentence is the whole test. There is no default depth, no default duration, and no default orientation. The depth and time you see on a certificate were chosen by whoever commissioned the test, which is why the same article can legitimately carry IPX8 at 1.5 m and IPX8 at 5 m.

A credible IPX8 claim therefore has to be printed as a pair, never as a bare code. Ask for the format IPX8, 2 m / 60 min or equivalent, and treat any certificate that says only IPX8 as incomplete. When you compare two suppliers, compare the pairs. A supplier offering IPX8 at 1.5 m for 30 minutes is offering essentially IPX7 plus a small margin, and if the quote is higher for that, the premium is buying you marketing copy rather than engineering.

The declaration should carry more than depth and time. Require the maker to state whether the bag was tested empty or loaded, in what orientation, in fresh water or salt water, and whether the test was run on first-article samples or on samples taken after abrasion or laundering. Each of those variables moves the result, and a supplier who will not write them down is usually one who has not measured the sensitivity of the design.

1. Declared depth in metres and duration in minutes, printed next to the code on the certificate and on the spec sheet.
2. Water type: fresh, chlorinated pool water or 3.5 percent salt solution, since salt changes fabric wetting behaviour.
3. Load state: empty, or filled to a stated percentage with a stated ballast, and the orientation during immersion.
4. Sample provenance: first-article units, or units pulled from a production lot after abrasion or wash conditioning.
5. Pass criterion: mass gain of internal indicator tissue, or another measurable threshold rather than a visual judgement.

There is a commercial reason to push for this level of detail. If you sell into the EU or the US and your packaging carries a depth claim, the claim has to be substantiated. A bare IPX8 does not substantiate anything, because nobody can reconstruct what was tested. The documented pair does, and it is also what your customer's own compliance team will ask for when they audit you.

Depth, Duration and the Missing Numbers

Water pressure rises by roughly 0.1 bar per metre of depth, so 1 m adds about 9.8 kPa and 3 m adds about 29 kPa. These are small numbers compared with the pressures a fabric survives in hydrostatic head testing, where 10 000 mm is about 1 bar. The reason an immersion test is harder than the arithmetic suggests is that the closure, not the fabric, is the weak link, and a closure fails by geometry and creep rather than by pressure alone.

Duration is the variable buyers underestimate. A coated fabric under standing load creeps, a welded seam relaxes, and a zipper tape absorbs water along its edges and slowly wicks. A design that holds for 30 minutes can weep at 90 minutes with no change in depth. If your use case involves long submersion, specify the duration explicitly and ask for the test at that duration rather than assuming the IPX7 window covers it.

One more missing number is temperature. Immersion in cold water stiffens PVC coatings and can open a marginal weld, while warm water softens TPU and lets a roll-top relax. If your market includes Scandinavian winter paddling or tropical dive boats, specify a conditioning temperature for the test, for example 12 hours at 5 °C before immersion, and ask for the test to be run in water at the same temperature. Our low-temperature flexibility work exists precisely because ambient-temperature test data misleads on winter returns.

Finally, watch for the hydrostatic short cut. Some suppliers quote a hydrostatic head figure, such as 10 000 mm, and imply it equals IPX7. It does not. ISO 811 measures fabric resistance to a column of water pressing on a clamped flat specimen; it says nothing about the roll-top, the zipper, the seam or the shape. Use hydrostatic head and the IP immersion test together, and never let one substitute for the other in a specification.

Construction Needed to Hold IPX7 vs IPX8

For a soft good, IPX7 is usually achieved by three things working together: a welded or seam-sealed body, a closure that folds rather than fastens, and enough material stiffness to keep the fold tight. A radio-frequency welded seam on TPU-coated fabric routinely outperforms a sewn-and-taped seam in immersion, because there is no needle hole path. On a 500D or 840D TPU laminate, IPX7 is a comfortable target rather than a stretch.

IPX8 raises the bar on the closure, not really on the fabric. Once the fabric passes 10 000 to 20 000 mm hydrostatic head, extra head buys you nothing at 2 m, because the pressure at that depth is a fraction of what the fabric already survives. What changes is the demand on the roll-top: more rolls, a stiffer stiffener bar, and a buckle that keeps compression on the fold. Where a customer wants a zipper instead of a roll-top, we steer them to a waterproof zipper with welded tape and a secondary storm flap, because a coil zipper alone will not hold IPX8 reliably.

• Body: RF-welded TPU laminate, 500D to 840D, welded seam peel strength recorded per batch.
• Closure for IPX7: three-roll roll-top with a stiffener, or a water-resistant zipper under a storm flap.
• Closure for IPX8: four-roll roll-top with compression buckle, or a hard-shell insert with a gasketed lid.
• Hardware: welded D-rings and bar-tacked webbing anchor points, since strap holes are a common leak path.
• Valves: welded, not sewn, and pressure-decay checked on 100 percent of units if the design uses an air valve.

Geometry also decides the outcome. A tall narrow bag traps more air and floats harder, which pushes the roll-top toward the surface and can partially uncover it, and it also increases the pressure differential across the lower seams. A squat wide bag submerges more calmly. If your design is tall and the target is IPX8, plan on a weight-loading protocol in the test so the specimen does not fight the water and give you a falsely optimistic pass.

Do not forget the path of least resistance outside the seams. Stitching at strap anchors, a label sewn through the body, a poorly welded valve, and a clear window all fail before the main panel does. On our 50 L dry bag OEM programme we qualify each sub-assembly separately before the whole bag goes into the tank, because a single failed valve on a 30-minute test tells you nothing about the other nineteen features.

Cost Difference in Real Quotes

The jump from IPX7 to IPX8 rarely comes from the fabric. Both targets sit inside the same 10 000 to 20 000 mm hydrostatic head band that technical dry bags already use, so the laminate cost does not move much. The cost moves because of the closure, the tooling, the test burden and the yield. A waterproof zipper costs several times a standard coil zipper and must be applied on dedicated equipment, and a stiffer roll-top stiffener plus compression buckle adds both part cost and assembly time.

The second cost driver is validation. Each style and colourway needs its own qualification, and if you want the rating printed on packaging you need a third-party report per SKU family. On our side the commercial frame is fixed and predictable: MOQ 500 pcs per style and colourway, sampling in 6 to 10 working days, or 12 to 15 working days when the construction is complex, and bulk production in 35 to 50 days. Every shipment is inspected to AQL 2.5 (ISO 2859-1), quoted FOB Xiamen on T/T 30/70.

Yield is the third driver and the one that surprises buyers. If a design sits right at the edge of its rating, the pass rate on the production water-test pull drops, and the cost of rework and scrap is larger than the cost of the extra zipper you declined. Spending a little more on a closure that passes with margin is almost always cheaper than running a design at its limit. Ask your supplier for the pass rate on their daily pull, not just the pass rate on the golden sample.

Where the budget genuinely cannot absorb a waterproof zipper, the honest answer is to redesign for IPX7 with a roll-top rather than to chase IPX8 with marginal hardware. A roll-top 20 L dry bag at IPX7 sells well and returns few complaints. The same bag claimed at IPX8 with a marginal zipper generates warranty claims, marketplace disputes and, in the worst case, a substantiation problem. See our OEM development process for how we cost both routes against your target retail band.

Which Products Belong at Each Rating

Match the rating to the failure mode you are actually protecting against. Paddle sports and marine use produce short, shallow, accidental immersion, which is IPX7 territory. Dive support, long tows behind a boat, and anything stored submerged for hours are IPX8 territory. Rain exposure with no immersion at all is better served by a spray rating plus a hydrostatic head figure, and a hiking pack that only ever sees rain should not be sold as an immersion product at all.

Two categories deserve a warning. First, waterproof hiking backpacks: a pack with a sewn harness, a lid and external pockets has dozens of stitch lines, and claiming IPX7 for it invites returns from customers who submerged it and found water in a pocket. Sell the rain performance honestly and put the immersion rating only on the dry-bag core if the design has one. Second, fashion-led totes and duffels: customers buy them for looks and expect light rain protection, and a genuine IPX7 claim there adds cost nobody will pay for.

If you are building a range, consider two tiers rather than one. A core IPX7 line in three sizes covers most of the market and shares tooling and fabric across sizes, which protects your MOQ position. A single IPX8 hero SKU at the top of the range gives the marketing team a depth claim without forcing the whole catalogue through expensive validation. Our standard waterproof bag range is structured exactly this way.

Writing the Rating Into a Tech Pack

A rating is only as strong as the sentence that carries it. Write the standard, the condition, the sample count, the conditioning and the pass criterion in one block, so there is nothing left to interpret on the production floor or at the inspection table. Vague lines such as waterproof IPX8 are where disputes start, because the supplier's reasonable interpretation and yours will differ by the time 5 000 units are packed.

Use wording along these lines: Ingress protection: IPX7 per IEC 60529. Immersion 30 minutes, lowest point of the article 1 000 mm below the water surface, highest point at least 150 mm below surface. Fresh water, specimen and water temperature within 5 K. Sample size 3 units per colourway, conditioned 24 hours at 20 °C and 65 percent RH. Pass criterion: no mass gain of the internal indicator tissue and no visible moisture on the internal indicator card. For IPX8, replace the depth and duration line with your own declared pair.

1. Name the standard and edition: IEC 60529, plus the declared depth and duration for any IPX8 claim.
2. State the sample count and conditioning, including temperature and humidity before the test.
3. Define a measurable pass criterion, never a subjective visual one.
4. Add a per-lot verification pull under AQL 2.5 (ISO 2859-1) so the rating survives into production.
5. Require the full test report with photographs of the setup, not a certificate summary page.
6. Record which lab ran the test and whether it was an internal or third-party facility.

Close the loop with paperwork discipline. Our SGS-verified facility keeps immersion records, weld-parameter logs and hydrostatic head certificates together per production order, and the technical specification sheet we issue carries the same wording as your RFQ, so the buyer, the lab and the line are all reading one sentence. If you want a second opinion before you commit, our team will review your draft wording and flag anything that cannot be tested as written.

Frequently Asked Questions

Q1: What is the difference between IPX7 and IPX8 for a waterproof bag?

A: IPX7 is a fixed test condition defined by IEC 60529: 30 minutes of immersion with the lowest point of the article about 1 000 mm below the water surface. IPX8 is an open condition that must be more severe than IPX7, but the depth and duration are chosen by the manufacturer and agreed with the purchaser, so the numbers must be printed next to the code for the claim to mean anything.

Q2: Is IPX8 always better than IPX7?

A: No. IPX8 only has to be more severe than IPX7, and the maker chooses how much more. A bag certified IPX8 at 1.5 m for 30 minutes is barely above IPX7 and gives you no practical advantage, while another certified at 3 m for 60 minutes is a much stronger product. Always compare the declared depth and duration rather than the two-character code alone.

Q3: How deep is IPX7 in metres?

A: IPX7 places the lowest point of the enclosure roughly 1 000 mm below the water surface and requires the highest point to be at least 150 mm below the surface so that the whole article stays submerged. It is a shallow but fully enclosing test, and it lasts 30 minutes. It is designed as a margin over an accidental drop into water, not as a diving specification.

Q4: Can a dry bag with a roll-top closure pass IPX8?

A: Yes, provided the closure is designed for it. A three-roll roll-top is comfortable at IPX7; moving to IPX8 usually needs a fourth roll, a stiffer stiffener bar and a buckle that maintains compression on the fold through the whole test. The fabric is rarely the limiting factor once hydrostatic head exceeds 10 000 mm, because the pressure at 2 m is small compared with the fabric rating.

Q5: Why do suppliers quote hydrostatic head instead of an IP rating?

A: Hydrostatic head, measured under ISO 811 or AATCC 127, is a fabric test on a flat clamped specimen and is cheap and repeatable. An immersion test under IEC 60529 evaluates the whole assembled article including seams and closure, which is harder and more expensive. The two measurements answer different questions, so a hydrostatic figure cannot be converted into an IPX rating.

Q6: Does IPX7 mean the bag can go underwater for 30 minutes repeatedly?

A: The test qualifies one 30-minute immersion on conditioned samples, not repeated cycles. In service, salt, sand and grit in the roll-top can hold the closure open and cause a leak on the second or third dunk. If repeat exposure is realistic for your product, specify a cycling protocol with drying intervals and inspection of the closure between cycles.

Q7: What should an IPX8 certificate show to be credible?

A: It should show depth and duration next to the code, for example IPX8 at 2 m for 60 minutes, plus water type, load state, orientation, sample provenance and a measurable pass criterion. A certificate that simply says IPX8 without those fields cannot be audited or substantiated, and you should treat it as marketing language rather than as a tested result.

Q8: How much more does an IPX8 bag cost to make than an IPX7 bag?

A: The fabric cost is nearly identical because both targets sit inside the same hydrostatic head band used for technical dry bags. The extra cost comes from the closure, such as a waterproof zipper or a stiffer roll-top assembly, from additional tooling, from per-SKU validation, and from lower yield if the design sits at the edge of its rating.

Q9: Should a waterproof hiking backpack be specified at IPX7?

A: Usually not. A hiking pack has a sewn harness, a lid and external pockets with many stitch lines, and its realistic exposure is sustained rain rather than immersion. A spray rating plus a hydrostatic head figure of 10 000 mm is a more honest and more defensible specification, and it avoids returns from customers who submerge the pack and find water in a pocket.

Q10: What is the right pass criterion for an immersion test on a bag?

A: Use a measurable one. Place a weighed indicator tissue or an indicator card inside the bag before the test and require zero mass gain and no visible moisture after the full immersion period. Avoid a purely visual criterion, because different inspectors will reach different conclusions and the disagreement will surface at the pre-shipment inspection rather than in development.

Q11: How many samples should be tested to qualify a rating?

A: IEC 60529 does not fix a production sampling plan, so a common practice is three units per colourway or per material lot, conditioned before testing. That qualifies the design only. To keep the rating true in production, add a per-lot water-test pull governed by AQL 2.5 under ISO 2859-1 and ask your supplier for the pass rate on that pull rather than on golden samples.

Q12: Does water temperature change the IPX7 result?

A: Yes. Cold water stiffens PVC coatings and can open a marginal weld, while warm water softens TPU and lets a roll-top relax. IEC 60529 asks that the specimen and the water be at similar temperatures to avoid misleading pressure effects. If your market includes winter paddling or tropical use, add a conditioning step, such as 12 hours at 5 °C, before immersion.

Q13: Can I claim IPX7 on packaging if only the fabric was tested?

A: No. IPX7 under IEC 60529 is an article-level immersion test, and a hydrostatic head result on fabric says nothing about seams, closures, valves or geometry. Claiming IPX7 on the basis of fabric data alone is not substantiated and creates exposure with marketplaces and with consumer protection authorities in several export markets.

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