Is My Pool Cover a Safety Cover?

Read the label. That is the test.

Find the label sewn or riveted to your cover and look for a classification. ASTM F1346 puts every pool cover into one of three named classes, and clause 8.12 requires the label to state which class the product holds. A Power Safety Cover or a Manual Safety Cover is a safety cover. Anything else is not, and a cover that is not one has to say so on its label in plain words. No label, or one you cannot read, means unverified, and unverified means you treat it as a winter cover.

The three classes, and why the third one matters most

Section 4 sets out the cover classifications, and there are exactly three.

Here is the part almost nobody publishes. An Other Cover is not a weaker safety cover. It is a class that passes no performance test whatsoever. Clause 4.3.1 asks it to satisfy the materials clauses and the labeling clauses, and stops. No weight test, no drainage test, no openings test, no perimeter test.

Your blue winter tarp, solar blanket and leaf cover all land there. The standard names each and routes it back to Other Covers, to be taken off completely before anybody swims.

How to read the label, line by line

Section 8 binds every cover, safe or not, so a warning label proves nothing by itself.

On every cover

• The manufacturer or responsible party, which may be a private label distributor.
• The signal word WARNING, preceded by a triangle holding an exclamation point, at least as tall as the signal word's letters.
• Directly below it, the fixed message AVOID DROWNING RISK. It has to come first.
• Then the hazard statements that apply, from the chart at Figure 1: stay off a cover that will not take weight, a child underneath cannot be seen, clear standing water, remove the cover before anyone swims.

Only on a safety cover

Clause 6.3 adds three markings an Other Cover does not need: the manufacturer's name, the date of manufacture or installation, and a direction to inspect for early wear and deterioration.

Only on a cover that is not one

Two tells. The last row of Figure 1 makes a cover that fails the safety requirements add a statement that it is not a safety cover, flat, in those words. And color: clause 8.3 prints its signal word black on an orange panel, with a black alert triangle holding an orange exclamation point. Clause 8.4, the color clause, is written for the two safety classes only, so orange means not a safety cover.

The label must be permanent, or at least hard to remove, and sit where fitting will not strip it. If yours is gone or unreadable, clause 8.9 says to ask the manufacturer for replacements.

What a safety cover has to survive

Static load: 485 lb, in three pieces

For a pool whose width or diameter is more than 8 ft, the cover has to hold 485 lb. At 8 ft or under, 275 lb. Careful, because this is widely garbled: the 8 ft measures the pool, not the cover, and not the drop from the cover edge to the water. Nearly every residential pool is wider than that, so yours is a 485 lb cover. The 275 lb case is spas and small wading pools.

485 lb stands for two adults plus a child, sized for a rescue. It does not arrive as one block. Three weights go on: 225 lb, 210 lb and 50 lb, each spread across a square foot, all three inside a 3 ft radius, for 5 minutes. Then the same load moves between attachment points, 4 to 6 ft in from the pool wall, where covers give way. Nothing may tear enough to let a weight through.

Perimeter deflection

Put 50 lb on the cover 4 to 6 ft in from the side and it must not sag far enough to open a gap at the edge. What has to be kept out is an ellipsoid, 3.7 in by 5.7 in and at least 12 in long, weighing 36.6 lb. The scenario: one child falls onto the cover, and the test asks whether a second could slide into the water down the side.

Openings: a 4.5 in sphere under 40 lb

No opening in the cover, and no gap at its edge, may let through a solid faced sphere 4.5 in across when 40 lb, give or take a pound, is pushed steadily against it. Clause 7.4 makes it a strength requirement too: the opening must not be forceable to a size that passes the sphere. The 4.5 in is head breadth, measured on a fifth percentile seven month old, the age at which half of babies can creep on hands and knees and reach a pool unaided.

Drainage: 30 minutes, judged by a toddler shape

A safety cover has to shed substantially all standing water within 30 minutes of the rain letting up. The lab version of rain is a spray applied evenly at 10 gal a minute for every 1,000 sq ft of pool, for half an hour.

The pass mark is not dryness. A torso shaped object stands in for a three year old: 32 in long, 9 in wide and 5 in deep, weighing 36.6 lb. It lies face up, parallel to the edge and two to three feet in from it. Three minutes later the cover fails if the water still there completely covers that torso. Plainly: drain fast enough that a small child could not drown in the puddle on top. Residual water is expected.

Through both load tests every anchor, strap, spring and control has to stay closed and keep working. Fastenings also have to resist a child: a key, a lock, a special tool, or a spot 5 ft up with nothing to climb.

Two things you will read that are not true

"A safety cover will not let more than one inch of water collect." That line is everywhere and it is not in the standard. There is no one inch figure in F1346, anywhere. The real rule is the one above, judged by whether what remains would swallow a 36.6 lb toddler shape laid on the cover. A listing quoting you an inch is copying a secondary summary, not the specification.

"The openings have to stop a 4 inch ball." Both numbers are real and they belong to different documents. F1346 uses a 4.5 in sphere at 40 lb for openings in a cover. The 4 in sphere is the barrier rule, used by the model swimming pool and spa code and the federal barrier guidelines to measure the gaps in a fence. Judge a cover at 4.5 in and a fence at 4 in.

A note on our own accuracy. Every clause and figure here comes from the published text of F1346, adopted in 1991 and reapproved since. The current revision, F1346-23, is paywalled and we have not read it.

There is no certification, and that is not a scandal

Search the published standard for the word and it does not appear. ASTM writes specifications. It does not test products, approve them or list them. Its own catalog entry calls F1346 a specification with performance tests that show compliance or noncompliance.

A cover claiming F1346 is saying one of two things. Usually it is a manufacturer's declaration: the manufacturer states that its cover meets, or meets and exceeds, the performance requirements. It rests on the manufacturer's own testing. The stronger one is an independent lab evaluation, which here means UL. Underwriters Laboratories runs classification programs, and some powered cover manufacturers give a UL file number with a statement that UL classified the system as a power safety cover to F1346. Ask for that number.

Be suspicious of the standard's number followed by "certified", "approved" or "rated". The standards body does none of those three things. Sound phrasings are "meets ASTM F1346", "built to ASTM F1346", and, where a file number backs it, "UL Classified to ASTM F1346".

Does a safety cover replace a fence?

In most places, no. This is the question where a comfortable answer gets somebody hurt.

The International Swimming Pool and Spa Code, the model most jurisdictions build on, waives the barrier sections in two cases: a spa or hot tub with a lockable F1346 cover, and a swimming pool with a powered F1346 cover. The code body's commentary is explicit: a manually installed cover does not earn that relief even when it complies, because putting one on by hand is involved enough that it would not be done every time the pool goes unused. The federal barrier guidelines say powered too.

States layer their own rules on top. California is the permissive end: its pool safety statute lists a safety pool cover, manual or powered, among the qualifying drowning prevention features, and the test it sets is the label, which has to verify the cover meets the F1346-23 specification. New York is the strict end: a swimming pool needs its permanent barrier whether or not a safety cover is fitted, though a spa with a complying cover is exempt.

Every safety cover we sell is a manual one. Under the model code that is not a fence substitute. Check your local code and keep the fence.

Above ground pools

Wading pools, hot tubs, spas and swimming pools are all inside the scope, and above ground pools are never carved out of it. They are never discussed either, and the tests show why.

The openings test measures the gap where the cover edge meets a deck, a coping wall or the top of the pool. A deck, in the standard's definition, is the area abutting the pool built of wood, concrete, brick or stone, and it may carry the cover's supports. The load and deflection tests want anchor points several feet in from the pool wall. An above ground pool standing on grass has none of that.

That last step is our reading, not a line in the standard. The conclusion holds either way: a cover winched down on a cable, or clipped to the top rail, is an Other Cover. If you meet one advertised against F1346, ask which of the three classes its label names.

What this means when you are shopping

Every cover on our safety cover pages is a Manual Safety Cover: fabric panels held over the water by straps, springs and anchors set into the deck. A mesh cover such as the King99 passes rain and snowmelt through the weave, which clears the 30 minute drainage rule and is why mesh needs no pump on top of it. A solid cover such as the Emperor blocks the light instead and moves water off through a drain panel or a cover pump.

The anchors are not an accessory. They are what the load and deflection tests are really measuring, because a cover only holds 485 lb if what it is tied to holds 485 lb too. In a concrete deck that means a brass anchor set into the slab, raised with a 1/4 in hex key to take the spring and screwed back flush for the swimming season. Brass, because it spends its life in wet concrete.

Then do the thing this page is about. Find the label, read the classification, and keep the sheet with the date on it.