Aquatic Technology Pool & Spa, "Creating Water as Art."™

Aquatic Technology Pool & Spa, "Creating Water as Art."™
Pools as an art form - the way it should be!

Sunday, June 3, 2012

How does a Vanishing Infinity Negative or Knife Edge Pool Work?

How does a Vanishing Infinity Negative or Knife Edge Swimming Pool Work?

Knife, Infinity or Vanishing Edge Pools do not require a water over water or horizon view.  In fact some of the most remarkable edge pools are set in flat yards with views into woods or lush foliage.  The generic term for a pool that overflows one or more sides is a "water in transit" pool.

Edge Definitions

Infinity, negative, disappearing and vanishing edge pool are all the same.  The phrases are used interchangeably.  These pools typically have one side slightly lower that the others, over which water flows.

Knife edge pools are usually built on flat lots (though I have done combinations of knife edges and vanishing edges).  Knife edge pools appear to be normal pools with the water level operating almost even with the top of the coping or deck.  There is a diagonal slot in the face of the pool, into which the water overflows.  These are by far the most complex of the styles to master.

Slot overflows pools are pools that look as though someone left the fill water on, and the water has flowed up and onto the deck.  A narrow slot in the deck collects this water.

A gutter overflow pool, is a pool where the water flows over a rim and into a gutter.  The gutter can be in the face of the pool (inside the pool and below the deck - as in an competition pool.  Or the gutter can be set into the deck.  The pool is technically a perimeter gutter overflow pool.

A flooded deck pool is any pool where the water flows over the walls of the pool and onto the deck.  This can be a perimeter slot or gutter pool.

Perimeter overflow pools is a generic term that describes water flowing over the perimeter of the pool.  The edge details can be vanishing edges, knife edges, flooded decks, slot or gutter overflows.

Water in Transit

The key to making any of these pools operate correctly is to understand the hydraulics involved.  Each technique requires a different rate of flow.  If the techniques are combined, one cannot simply provide for the greatest flow rate required - it will flood or overflow the details that require less flow.

Every one of these pools requires that some water be stored outside of the main pool.  This can be an attached basin, a remote tank or a combination of the two.  The holding tanks must also be able to have the capacity to store water displaced by swimmers, wind and weather.

Remote holding tanks require an even greater understanding of hydraulics.  The water flows from the primary pool to these tanks via gravity.  The slope and diameter of the gravity drain line dictates the flow capacity of these lines - to a point.

Basics of Operation

Water from the holding tank is pumped to the primary pool.  The water over flows the edge(s) and drains back to the holding tank.  There must be enough water in the holding tank to fill all of the lines, raise the level of the pool to flood the edges, and fill the gravity drain lines back to the storage tank.  The most common mistakes are undersized holding tanks and plumbing lines.

Having a keen grasp of the hydraulic requirements of the various edge details is paramount when designing or constructing such pools.  Gone are the 1.5 and 2" plumbing that most pool builders are accustom to.

A failure on one of these pools can be an expensive repair - something that most swimming pool builders cannot afford to repair out of their pocket.  That leaves the property owner footing the repair bill!

You only pay for quality once!

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool and Spa