Hidden Problems
A survey of your pool can highlight problems you can't see and help solve them cost effectively

By Erik D.W. Greven, P.E., Harriman Associates, and Winthrop S. Knox, Northeast Aquatic Design

Problems in aging pool facilities are often apparent. Tiles missing from the deck, a suspended ceiling that sags, rust around door frames, or high humidity. And the solutions may seem just as apparent — replace the tiles, install a new ceiling, paint the door frames, and upgrade the HVAC. Unfortunately, this approach may miss underlying causes that are even more serious than those that are visible, and it may not even be the most cost effective.

A better strategy is to conduct a thorough facility assessment -- the pool and its systems, and the building envelope and its systems. This will uncover problems that aren't apparent and that often affect safety or structural issues, and it will become the basis for deciding what to repair, what to replace, and the timetable to do it.

The process

Building systems
--Mechanical
--Structural
--Electrical

Pool systems
--Pool structure
--Filtration
--Circulation
--Chemical treatment

The process
A periodic survey of existing conditions -- perhaps every 10 years -- is especially important for a pool facility, where water, humidity, and chemicals create a harsh, corrosive environment. Pools that are more than a decade old are particularly vulnerable, not only due to the length of time within that environment, but also because earlier systems were not as good at handling the effects of corrosion.

A comprehensive facility survey will uncover all problems and help determine the best way to deal with them. A survey also presents an opportunity to assess changes in the use of the pool that have occurred through the years and to make upgrades to systems and correct problems in a way that is compatible.

The study should be performed by a team of architects, engineers, and pool-design specialists. This combination of professional expertise results in a broad perspective that considers all systems. Their approach is in contrast to that of vendors representing a particular product. While vendors may know their own systems and equipment well, the interrelationships and causes and effects among systems require broader knowledge to address adequately. When a pool facility has been in service for many years, a more comprehensive approach is warranted.

Pool systems and the buildings that house them consist of hundreds of distinct parts that must function properly, not only on an individual basis but in relation to each other. Add to that the corrosive nature of the environment and the correction for a problem in one part or system may lie in a completely different area. Critical parts of many systems are not visible, adding to the difficulty. A repair that appears to be the most logical and cost-effective solution may in fact end up being the most expensive, because correcting the real problem can be more costly later.

The team looks carefully and methodically at the systems and their components, noting which work properly and which do not. Their report presents options for correcting problems and estimates costs, as well as priorities for a plan of action. Safety considerations and code issues are thoroughly addressed. In considering options and alternative actions, payback is calculated so that the benefits can be compared with costs.

A facility survey will include both building and pool systems -- the mechanical, electrical, and structural systems in the building and the filtration, circulation, and chemical treatment systems for the pool as well as the pool structure itself. The specific components examined in a survey will depend on the individual pool and facility, just as the problems discovered and what is suggested to solve them will also vary. But understanding some of the more important problems that may be uncovered in each of the major systems and how they might be corrected can provide a building owner with a sense of what to expect.
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Building systems
Mechanical system. If you stand on the edge of an indoor pool in street clothes and feel uncomfortable, it's a good bet that there are humidity problems in the building. That's an indication that the heating, ventilating, and air conditioning system is not handling the moist air that comes from the pool properly.

Humid air creates problems in any type of building, but when the chemicals used to purify pool water are also present, the damage can be extensive. Anything the air comes in contact with — pipes, ducts, heating coils, even steel building supports -- can become corroded.

While it might seem that replacing a corroded pipe or duct would be enough, if the damage is being caused by faulty ventilation, it will recur unless the solution addresses the root of the problem. In a facility survey, mechanical engineers can ascertain whether the flow of air and the humidity levels are causing the damage and will offer suggestions on how it can be corrected.

The correction may involve replacement and redesign of the entire system or of individual components. It may also be necessary to establish lower air pressure in the pool area than in adjoining areas to keep contaminated air from dispersing to other parts of the building where it could create problems. One way to do this is to exhaust more air from the pool area than is supplied to it. Exhausting air keeps the pressure in the area lower than that in adjoining areas. Uncontaminated air from adjoining areas then tends to move into the pool area and less pool air moves to adjacent spaces. This minimizes the chance that corrosion of building areas will spread.
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Structural system. Structural problems can be hard to identify and can cause the most serious safety issues. The symptom for a critical problem could be as innocuous as a broken or cracked tile. This is especially true for older pools that were built with a tunnel under the decks to make access to piping easier or that have air ducts alongside the pool walls. While their design made maintenance easier and provided a space-saving area for duct work, they also created an opportunity for structural damage.

The appearance of concrete can be deceiving. It may look sound, but can be so saturated with chlorine that it could disintegrate under stress. Even if the pool does not have tunnels, ducts, or other open areas such as offices along its sides, damage can be substantial.

At one community pool, broken and cracked tiles and inadequate drainage on a pool deck led an assessment team to go further than to recommend new tiles and grouting. They checked the structural system under the deck by drilling core samples of the concrete and having them tested.

While it appeared that the problem with the deck was superficial, the team discovered that chlorinated water had not only seeped into the structural concrete slab below the deck, but had also contributed to deterioration of the steel rebar within the concrete, compromising its strength. Had the most obvious solution to the problem been carried out, the situation would have worsened and a sudden collapse of the deck might have resulted.

Contaminated air also has the potential to damage the steel structure or supporting elements of the roof and ceiling. Like the damage to corroded concrete, damage to structural supports can cause catastrophic results, as it did in one community pool where a roof collapsed. An inadequate ventilation system had kept warm, chlorine-laden air drifting to the ceiling, and after several caused the damage. If the pool facility has a suspended ceiling, damage to structural elements may not be visible, but the problem would be obvious for a survey team that included structural engineers.
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Electrical system Like any other system in the building, the electrical system can be affected by a corrosive environment. A survey checks power panels, wiring, and lighting as well as paging and fire- alarm systems.

Frayed or exposed wiring will be noted and the circuit breakers checked. Evidence of rust on metal parts will be investigated to determine the extent of problems caused by humidity and pool chemicals, since the result can cause electrical malfunctions or even safety problems.

Infrared thermal scans are used to determine "hot spots" that indicate overheating at connection points, especially in circuit breakers. This could indicate that corrosion has affected the breaker and would prevent it from tripping when it should.

Lighting fixtures over the pool can be affected both functionally and structurally by the pool environment. The fixtures may not operate if there is significant corrosion, and if ceiling parts to which the fixtures are attached have been affected, the fixtures may fall.

A survey will also determine whether lighting levels are adequate for the way the pool is being used. Competitive swimming, for example, requires higher foot-candles than recreational use, according to recommendations by the Illuminating Engineering Society. The condition of emergency lighting systems will also be part of a survey as well as a determination of whether requirements of the National Fire Protection Association are met.
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Pool systems
Pool structure. Deciding what to do about leaks in a pool can also be better addressed with information from an independent facility assessment. Like other problems that arise, the source of the leak may not be the one that is the most obvious, and a team with diverse expertise has advantages.

The pool structure is usually not the cause of most leaks, rather their source is more apt to be piping, gutters, or drains that are not functioning properly. If these components have no defects, then the pool structure is carefully evaluated.

Again, the corrosive characteristics of the chemicals and water seeping into the concrete can cause devastating damage. Aluminum and steel pools can suffer a different sort of damage not easily seen. The long-term contact between the aluminum or steel, the water, and the concrete at the deck edge can cause an electrolytic reaction that eats away at the pool, much like a battery. Sometimes it can be cost- effective to remove the damaged part and replace it. But repair isn't always possible if the chemical action is widespread.

When the finish on a pool shows signs of wear, repairing or replacing it may be warranted, as long as damage to structural elements have been ruled out. Ceramic tile will last from 50 to 75 years, so that makes repair worth considering. Plastic liners, fiberglass pools, or painted surfaces can be expected to last a much shorter time, between 5 to 12 years, so that becomes a factor in deciding how to address a problem. An assessment can point the way to the most cost-effective solution.
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Filtration system. Besides identifying problems caused by corrosion, a complete pool facility assessment will look carefully at the filtration system. Pipes, valves, pumps, tanks, and the filtration medium itself are potential problem areas. Pipes and tanks can leak, and valves can be inoperative, particularly in older systems where they are often corroded shut or open.

If sand is the filtration medium, a backwashing process is used to clean the filter. However, backwashing too frequently can cause channels to form, making the filtration process less efficient.

The size of the sand particles will also affect the efficiency of the cleansing process. If they are too big, they will allow too much debris to be recirculated; if they are too small, they will slow down the process. The wrong size can also cause create problems with pump operations. Sand can be replaced and maintenance procedures changed, but the assessment may also point to an upgrade of the entire filtration system.

Filtration systems that use diatomaceous earth are more efficient than sand filters because they are capable of handling smaller size particle faster. Labor costs to maintain them, however, are greater and replacing the diatomaceous earth and disposing of the waste material is more expensive than replacing sand filters, so those factors should be taken into consideration in determining whether to upgrade. Similar issues are addressed with cartridge filters in the analysis.
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Circulation system. An assessment of the circulation system involves checks of the piping, gutter or skimmer, surge tank, return pipes in the pool walls and floors, and main drain. Gutters and skimmers collect water displaced by bathers and send it to be filtered, so it is important that they function properly.

However, older systems may appear to be working, but may not be absorbing displaced water and quelling waves as they should. This could allow dirty water to splash back into the pool instead of being sent for filtration. When that type of problem is discovered, it is often better to replace the system.

The assessment will also determine whether the type of gutter is adequate for how the pool is being used. One type of gutter system, for example, tends to enhance the performance of competitive swimmers by an improved ability to quell waves.

Besides leaks, it is not uncommon for valves in the surge tanks in older pools to be "frozen" or rusted in place. Correcting problems is especially important, since a load-bearing deck is usually over the tank and therefore subject to corrosive activity. If the deck were to collapse, anyone on it could be seriously injured.

The main drain from which 20 percent of the pool's water is sent for filtration and the inlets that bring the filtered water back can pose different types of safety issues. Older grates on the main drain are often chrome-plated and subject to corrosion, and severely damaged drains could entrap a swimmer or the grates could come loose. Entrapment could also occur if the main drain grates are not properly sized to a minimum velocity.
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Chemical treatment system. The right balance of chemicals in the pool can minimize or eliminate the corrosive action that causes so many problems, so proper operation of the treatment system is essential, not only to purify the water for bathers but also to protect the facility.

A survey of the system will include examination of the feeders and injection points where the chemicals are introduced into the pool to determine if lines are damaged or plugged.

Most chemical treatment systems are easily serviced and repaired, but a survey in an aging pool offers an opportunity to examine the benefits of upgrading to a more advanced system. Many improvements have been made in equipment to give the same levels of purity with lower levels of corrosiveness. Adding analyzers that test the water and add the right chemicals automatically also offers benefits.
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Pool facilities give many years of good service before serious problems occur. And proper maintenance will go a long way towards getting the most out of the facility, especially making certain that pool chemicals are balanced correctly. That and a ventilation system that operates properly are first-line defenses.

But a time will come when deficiencies will be noted. It's then that a thorough survey of the entire facility can ascertain whether the problems are superficial or whether they pose safety hazards. A careful review of an entire facility may not only detect serious problems that might otherwise go undetected, but it can also serve as the foundation for a cost-effective strategy to correct them.

Written for Athletic Business, October 1999