AFO Aquatic Facility Operator flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Free chlorine

The chlorine available to disinfect - hypochlorous acid (HOCl) plus hypochlorite ion (OCl⁻). Measured by DPD test; it is the number compared against the health code minimum.

Combined chlorine

Total chlorine minus free chlorine. Mostly chloramines formed when chlorine reacts with nitrogen wastes such as sweat and urine; causes the 'chlorine' odor and eye irritation.

Breakpoint chlorination

Adding roughly ten times the combined chlorine reading as free chlorine to oxidize chloramines completely. The residual first falls, then rises sharply once breakpoint is passed.

Cyanuric acid

A chlorine stabilizer that shields free chlorine from sunlight destruction. Above about 50–100 ppm (code limits vary) it slows disinfection and can leave chlorine present but ineffective.

Langelier Saturation Index

A calculated number combining pH, temperature, calcium hardness, total alkalinity, and TDS that predicts whether water is scaling (positive) or corrosive (negative). Target −0.3 to +0.3.

Total alkalinity

The water's capacity to resist pH change, measured as ppm of carbonate and bicarbonate. Keep 80–120 ppm; low values let pH bounce, high values make pH hard to adjust.

Turnover time

The hours required to pass the entire pool volume through the filtration system once. Calculated as volume in gallons divided by flow in gpm, then divided by 60.

Required flow rate

Gallons per minute needed to achieve a target turnover: flow = volume ÷ (turnover hours × 60). A 60,000-gallon pool on a 6-hour turnover needs about 167 gpm.

Filter loading rate

The flow per square foot of filter media. Typical maxima: rapid sand 12–20 gpm/ft², DE 1–2 gpm/ft², cartridge 0.25–0.375 gpm/ft². Exceeding it forces debris into the pool.

Backwash trigger

Backwash when the filter influent gauge reads 8–10 psi above its clean starting value, when flow falls below the code-required rate, or per the manufacturer - not by calendar alone.

DE filter

A filter using diatomaceous earth as the septum coating; it polishes water to the finest clarity but must be recoated after each backwash. Loading rate 1–2 gpm/ft².

Skimmer weir

The floating flap at the skimmer throat. It should ride at the middle of the throat with water level at mid-weir; a stuck or missing weir stops surface debris capture.

Bather load

The maximum number of people allowed in the pool at once, usually computed as water surface area divided by 20 ft² in deep water or 15 ft² in shallow water.

Emergency action plan

A written, posted, and rehearsed procedure assigning roles for rescue, calling 911, crowd control, and EMS access. Drills are documented and repeated on a set schedule.

Spinal injury management

Immobilize the head in line with the spine, support the victim in the water, and do not remove them unless the airway is compromised or the scene is unsafe.

Chemical storage separation

Store oxidizers such as chlorine away from acids and never above them, since mixing the two releases chlorine gas. Use secondary containment sized for the largest container.

Safety vacuum release system

A device that breaks pump suction when it detects a blockage, releasing a trapped bather. Required by the VGB Act on single-blockable-outlet pools without dual drains.

Cavitation

Rumbling or gravel noise from a pump caused by restricted suction - clogged basket, closed valve, undersized line, or low water level. It damages the impeller and destroys flow.

Multiport valve positions

Filter for normal flow, Backwash to reverse flow to drain, Rinse to settle media, Waste to bypass the filter, Recirculate to bypass media, and Closed. Never turn it with the pump running.

GFCI testing

Push the test button on pool-area ground-fault receptacles monthly and record the result. A failed unit must be replaced before the pool reopens, since it protects bathers from shock.

Pump seal leak

Water dripping from beneath the pump housing indicates a failed shaft seal, which also admits air into the suction and causes loss of prime and cavitation.

Heat exchanger scaling

Mineral deposits on heater tubes caused by high pH, high calcium hardness, or high alkalinity. Scale insulates the tubes, cuts heat transfer, and can restrict flow enough to trip safety switches.

Daily operations log

A written record of free and combined chlorine, pH, flow, temperature, and clarity taken at opening and again during the day; most codes require it be kept on site.

Lifeguard rotation

Scheduled relief of guards every 20–30 minutes to counter vigilance decrement. Rotations should be documented, and a guard must not be reassigned without the break.

In-service training

Documented practice of rescue, CPR, AED, and emergency drills conducted after initial certification - commonly at least four hours per month for aquatics staff.

Water clarity standard

The pool's main drain must be clearly visible from the deck at the deep end. If it cannot be seen, the pool is closed until filtration and chemistry restore clarity.

Pre-service training

Orientation and skills verification completed by each employee before their first working shift, covering facility rules, emergency procedures, and their specific assigned duties.

Model Aquatic Health Code

A voluntary CDC-published set of design, operation, and safety standards for public pools. It becomes enforceable only when a state or local health department adopts it.

Virginia Graeme Baker Act

Federal law requiring VGB-compliant anti-entrapment drain covers on public pools and spas, plus a backup system such as dual drains, an SVRS, or a safety vacuum release.

Hazard Communication Standard

OSHA 29 CFR 1910.1200; requires safety data sheets for every chemical on site, labeled containers, and documented employee training on chemical hazards.

Diarrheal fecal response

Remove the stool, then raise free chlorine to 20 ppm at pH 7.5 and hold for 12.75 hours (CT 15,300) before reopening. Formed stool needs only 2 ppm for 25 minutes.

ADA pool access

The Americans with Disabilities Act requires at least one accessible means of pool entry - lift, sloped entry, or transfer wall - plus accessible routes and compliant signage.