Shower curtain 'blow-in'

Nobody likes the icky shower curtain liner blowing in against them while they shower.

It's called "blow-in," is that phenomenon, and it's caused by the vortex created by the shower spray.

The better the water pressure, the worse the blow-in.

Many avenues of attack against blow-in have arisen.

Ron Lieber wrote an excellent article for the September 30 Wall Street Journal about the long-standing problem and its many possible solutions.

It follows.
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Attack of the Sticky Shower Curtain

Physicists, designers tackle delicate problem of blow-in, but does anything work?

The campaign is on to fend off the unwanted advances of your shower curtain.

Shower curtain "blow-in," the experience of having a damp, sticky polyester liner sweep in and envelop your bare legs, has long been one of the unacknowledged nuisances of bathing.

Now, an unlikely coalition of physicists, bathroom-products makers, and lodging providers are trying to attack the problem.

One weapon: a new curved shower rod that creates a bigger distance between the shower curtain and a vulnerable rinser.

Wyndham International Inc., Starwood Hotels & Resorts Worldwide Inc.'s Westin chain, and Hilton Hotels Corp.'s Hampton Inn are all installing the curved shower rods in their bathrooms.

At the same time, a range of intuitive - though often flawed - solutions have appeared in stores and on the Web, from the more standard weighted magnets to curtains that attach to the wall.

Home-products superstore Bed Bath & Beyond Inc. now carries at least six different shower-curtain liners.

The priciest, the $19.99 "All in One Ultimate Shower Curtain Liner," introduced last year, features a two-sided fabric of polyester and vinyl that the packaging says "will not billow."

Then there's the "Shower Curtain Sealer" that a Brentwood Bay, British Columbia, company called StayDry Systems started selling two years ago.

The sealer attaches to the shower wall; a bather can tuck the shower curtain into it.

Scientific investigation of the sticky conundrum has been given new life by the curiosity of a determined physicist.

During one Christmas vacation a few years ago, David Schmidt, an assistant professor in the mechanical and industrial engineering department at the University of Massachusetts at Amherst, noticed that the curtain at his mother-in-law's house "just sucks in fabulously."

Since Dr. Schmidt's main area of research is fluid dynamics, he thought he'd take up the riddle of the billowing curtain during the break.

Other experts on fluids and physics had posited that the blow-in phenomenon might be related to either the Bernoulli effect, which helps explain why a plane's wings help lift the aircraft, or the "buoyancy theory," which relates to temperature and air pressure.

Dr. Schmidt tested the theories by using a software program to divide a typical shower area into 50,000 cells.

The result: a third idea - that the shower spray creates a vortex, a low-pressure region not unlike a cyclone, in the bath area. That, he says, is what pulls the curtain in.

It's an unfortunate paradox: The better the water pressure, the worse the blow-in.

Dr. Schmidt's theory drew unexpected renown.

But as far as he came toward understanding the physics, Dr. Schmidt hasn't actually come up with any solutions; indeed, he experiences a bit of blow-in at home.

Happily, Dr. Schmidt is not the only person working on the problem.

After spotting a curved shower-curtain rod in a magazine, Michael Smith, a Chicago-area sales and marketing director for Starwood Hotels, ripped out the page and sent it off to headquarters.

Westin eventually decided to use the curved rod in its new "Heavenly Bath" design, which is now in every U.S. Westin and is being rolled out overseas.

The centerpiece of the bathroom remodel was supposed to be a fancy double shower head.

The rod was merely designed to give people a bit more elbow room to enjoy the massaging spray.

But customer response also revealed the fact that the curtain had farther to blow in before it touched the bather. Guests loved taking showers unmolested by their curtains.

The lower-price Hampton Inn chain also added the curved rod as part of a bathroom overhaul.

One easy solution to the blow-in problem would have been to do away with curtains entirely.

But shower doors or separate stalls are expensive for hotels to install, and Hampton was looking to overhaul 129,000 guest rooms.

The Hampton Inn redo has already impressed frequent travelers.

"That shower curtain rod makes you want to go out and buy one," says David Newton, a Knoxville, Tenn., kitchen designer who leads training sessions for others in his field.

The curved rod is available online at stacksandstacks.com, thecurvedrod.net, and Westin's own Web site, westin.com. (Westin sold 1,600 curved rods last year.)

The price tag: $40 for a five-foot rod and $60 for a six-foot rod. Both will fit most tub areas without special installation.

For consumers looking to solve the problem, a variety of shower-curtain designs are available.

A recent shopping trip to Bed Bath & Beyond yielded a number of options.

At the low end was a "heavyweight" liner with magnets at the bottom.

In the middle was the curtain with suction cups along the sides and a weighted bottom.

The most expensive was a "super" weight curtain.

Weights or magnets on the bottom of the curtains seemed to make intuitive sense.

But a home test showed otherwise, since the curtains either overpowered them or billowed out around them.

The super weight came the closest to solving a bad blow-in problem in a test shower, though an anti-mildew treatment on it reeked.

There is a more drastic fix: Separate the bathtub from the shower and enclose the shower with glass, marble, or another solid surface.

Today's showers tend to be glass, rather than the old plastic, and their doors swing open rather than sliding on a track.

"These are not necessarily the shower doors from the 1970s," Mr. Newton says.