13.1 Facility Renovation and Design Considerations

13.1 Facility Renovation and Design Considerations

Quick Answer: Sit in the schematic meeting as the person who will open the pool at 6:30 a.m. Demand a turnover and surge volume that match the intended use, deck slope to deck drains (not into the water), a chemical storage space that is separate and independently ventilated, labeled emergency shutoffs, a filter room you can service, heater venting that cannot dump combustion products into the natatorium, accessible entries (Chapter 10), and dual main drains or another legal Virginia Graeme Baker path (Chapter 11). Plaster, paint, and liner jobs are not automatically “repairs.” The AHJ decides when work becomes an alteration that must meet current code. Bather load drives locker-room fixture demand in MAHC-style thinking; do not invent a national toilet table. Covers and VFDs save energy only if required flow still happens.

Aquatic Facility Operator (AFO) candidates meet this material as Operations domain topic 4D — Facility Renovation and Design. Daily opening, indoor air, and weatherizing are Chapter 12. Special amenities — water parks, spray pads, slides, water features, spas, and therapy pools — are Section 13.2. This section is the operator in the room with architects, civil engineers, and a bid that is already too low.

Independent OpenExamPrep teaching uses public 2024 MAHC design themes, CDC Healthy Swimming practice, CPSC drain-safety geometry, and ADA entry rules taught in Chapter 10. OpenExamPrep is not an NRPA, CDC, or health-department partner. The adopted local code is the document that can hold a certificate of occupancy.

Why the operator belongs in the design meeting

Architects optimize sight lines, locker counts on a floor plan, and a construction budget. Mechanical engineers optimize a pump curve on paper. The operator inherits actual GPM on a dirty filter, a chemical room that fumes into the pool, a surge tank that floods on Saturday, and a lift parked in a current. If you are not in the meeting, those mistakes get poured in concrete.

Bring a one-page list. You are not redrawing the building. You are naming the items that become daily closures when they are wrong.

Turnover that matches the use, not the brochure

Turnover is volume divided by flow: GPM = gallons / (turnover hours × 60). Chapter 6 owns the arithmetic. Design still has to pick the hours. A competition rectangle that the 2024 MAHC would file under “all other pools” is commonly modeled at 6 hours or less. An activity pool, wave pool, or lazy river is commonly modeled shorter (often 2 hours or less in that same MAHC table). A hot spa is commonly modeled at 0.5 hours or less. Those are voluntary model maxima, not an NRPA national statute. Your AHJ may be stricter. The design trap is a leisure pool sold as a “family amenity” and then given a lap-pool pump.

If the intended program is lessons, parties, and a zero-depth beach, design the recirculation for that load. You cannot later invent flow with a sign that says “please splash less.”

Surge capacity: bathers displace water

Every person who enters the pool raises the waterline. Perimeter-overflow (gutter) systems send that extra water to a surge tank so the gutter lip keeps skimming. If the tank is undersized, gutters flood, water sheets across the deck, and then the waterline drops when the crowd leaves — skimmers starve, the pump sucks air, and the controller tastes a bubble. Skimmer pools have less surge storage; they fail as wild waterline swing and air in the strainer. In the meeting, ask what bather displacement the surge volume was sized for, and what happens at posted load plus a swim meet.

Deck slope and deck drains

Decks must shed water to deck drains, not back into the basin. Wash water, rain, spilled bleach, and tracked dirt that run into the pool become unplanned makeup and unplanned demand. Standing deck water is a slip hazard and an inspector photo. The exact slope is an AHJ and building-code number — do not memorize a fake national inches-per-foot figure as AFO law. The operator point is directional: away from the water, toward a drain that is actually piped and cleanable. Clogged deck drains are an operations problem you inherit from a drain that was specified without a cleanout.

Chemical room: separate, ventilated, not a boiler closet

MAHC-style design puts chemical storage in its own space: tight joints, a chemically resistant floor, protection from freezing and from temperatures above about 95°F (35°C), and no air movement from that room into occupied interior space. Acid and hypochlorite stay separated. Gas chlorine, where it still exists, has its own harsh rules (not below grade, tanks secured). The design failure you will live with is a shared mechanical closet: heater flue, chemical drums, and a door that opens into the pool hallway. Chapter 11 owns OSHA Hazard Communication. Design owns the box those drums sit in.

Ask for a room that exhausts outdoors, not into the natatorium air handler. Chapter 12 already taught that chemical-room air is not natatorium air.

Emergency shutoffs, filter-room layout, heater venting

Emergency shutoffs need to be labeled, reachable, and actually wired to the pump (and to spa jets or feature pumps where the code requires a separate cut). A shutoff behind a locked electrical room that only the city electrician can open is not an emergency device. Staff should be able to kill suction without solving a scavenger hunt while a hair entrapment is in progress.

Filter-room layout is maintenance access dressed up as architecture. You need space to open a filter, pull grids or cartridges, read gauges at eye level, isolate with valves, and backwash to waste with an air gap. Floor drains, lighting, bonding, and GFCI are not decorations. If the only path to the pump strainer is across a chemical spill berm, someone will skip the strainer.

Heater venting is combustion safety. Gas heaters need combustion air and a flue path that cannot dump carbon monoxide into the pool room. Do not share that air with the chemical store. High-limit and flow switches belong in Chapter 7; in the design meeting you only insist they exist, remain serviceable, and are not buried in a ceiling chase nobody can reach after the soffit is closed.

Accessible entries and dual main drains are design, then daily work

Chapter 10 owns ADA Title II/III and the 2010 Standards: pools under 300 linear feet of wall need one accessible means (lift or sloped entry); 300 feet or more need two, with at least one a lift or sloped entry. A spa cannot borrow a distant pool lift as its only entry. In design, locate the lift out of a river current, keep clear deck space, and provide a charging path that is not a 100-foot extension cord across a wet floor. The operator then tests the battery every open.

Chapter 11 owns the Virginia Graeme Baker Pool and Spa Safety Act (spell Graeme). Dual outlets at least 3 feet apart, an unblockable outlet, or a listed secondary anti-entrapment system are the public geometry. New construction and renovations that touch the floor are the cheap moment to put in two drains. Retrofitting a single-drain 1970s floor after plaster is the expensive moment.

Renovation versus repair: finish systems and the AHJ trigger

Owners love the word repair because it sounds like a weekend and a paint bid. Health departments love the word alteration because it can require current recirculation, drains, barriers, and accessibility. Your job is to know which job you are actually buying.

Plaster, paint, liner — what the operator inherits

• Cementitious plaster (often called marcite or quartz/pebble finishes on concrete shells) is a new interior surface. Surface prep usually means chipping, replacing waterline tile, resetting lights and return fittings, and exposing the drain sump. Fresh plaster thickness can bury or tilt a drain cover. A cover that was legal last season can sit too deep, too proud, or on the wrong sump geometry after the trowel. Plan new VGB-compliant covers and a measurement of the sump, not a hose-off and reopen.
• Paint on a sound shell is cheaper and returns faster. It also peels. Paint chips load filters, hide cracks, and get mistaken for algae. Paint in a drain sump can change how a cover seats. Recoating is still work the AHJ may want to know about if you are draining a public venue and changing fittings.
• Vinyl liner replacement is not “just plastic.” Walls get inspected, lights and returns get pulled, the hydrostatic relief valve gets a look, and the hopper (deep-end) geometry can change how a cover sits. A liner over a failing wall is a delay, not a repair.

None of those three is automatically exempt from permits. Like-for-like replacement of a failed pump motor is closer to repair. Changing horsepower, moving suction piping, adding a feature pump, or relocating a drain is not like-for-like.

When a “repair” becomes a code upgrade

The 2024 MAHC glossary defines a non-substantial alteration as renovation whose total cost is 50% or less of the replacement cost of the aquatic facility or venue. Work above that line is the model’s substantial path, and Chapter 4 design standards generally apply to new construction and substantial alteration. Your AHJ may use that 50% idea, a different percentage, a “change of equipment type” test, a volume change, or a simple “if you pull a building permit.” Do not invent a national NRPA dollar trigger. Ask the health department and the building official before the plasterer starts, not after the drain is already in the new floor.

Typical upgrade conversations during a basin project:

• Single main drain → dual drains, unblockable cover, or a listed secondary system
• Missing or expired drain covers → new listed covers with remaining service life
• Heater swap → current venting, GFCI, and bonding
• Pump swap to a different curve → flow meter, TDH, and turnover recalculation
• Adding a lift or sloped entry because the 2010 ADA Standards now apply to the altered area
• Chemical feed moving from an open tub to a day tank in a ventilated room

Worked example. A 1978 municipal rectangle has one floor outlet. The board approves “plaster only” at $180,000. Replacement cost of the venue is estimated far higher, so a 50% MAHC-style cost test might not fire — but the drain sump will be rebuilt, which is exactly when CPSC-style outlet geometry is cheapest to fix. You still flag dual drains or an SVRS, new covers, and a health-department alteration review. Calling it paint does not hide a new floor.

Bather load and locker-room fixtures (themes, not a fake table)

Posted bather load is a water-quality and drowning-prevention number, not a fire-marshal chair count. Many codes compute it from water surface area, with different factors for shallow water, deep water, and spas. Those factors are local. Independent teaching does not print a pretend national square-foot table and call it AFO law.

MAHC-style hygiene facilities (toilets, lavatories, cleansing showers, rinse showers, diaper-changing stations) are sized from theoretical peak occupancy — a design occupancy derived from water and deck area — and from applicable plumbing codes, often using the greater of the two. The operator takeaway is causal: if the locker room cannot handle the bodies you admit, the extra urine, feces, and dirt enter the pool. A splash-pad birthday with one toilet is a Crypto amplifier even if the controller reads 3 ppm.

You do not need to memorize unpublished fixture ratios. You do need to tell an architect that doubling the beach entry without doubling hygiene fixtures is a water-treatment project disguised as recreation.

Energy the operator inherits: covers and VFDs

Thermal covers cut evaporation and overnight heat loss. They are not safety covers. A safety cover is a barrier product (often discussed against ASTM F1346 in residential settings) with a different job: keep people off and out of a closed basin. Using a bubble blanket as a fence is a drowning setup. Using no cover on a heated indoor pool is an energy bill and a humidity bill (Chapter 12).

Variable-frequency drives let a pump run at the speed that produces required GPM instead of throttling a discharge valve on a full-speed motor. Affinity-law intuition is enough here: a modest speed drop can cut power a lot. The trap is running so slow that actual turnover exceeds the code maximum, inlets die, and the spa or feature starves. Design should set a minimum speed that still meets the plaque. Operators verify with the flow meter, not with the VFD keypad’s percentage.

LED lighting, high-efficiency heaters, and pool-water heat recovery from dehumidifiers are the same story: inherited tools. They do not excuse a missed residual.

Design decision versus operational consequence

If the bid cannot afford dual drains, a real chemical room, and a surge tank, it cannot afford a public pool. The operator’s job in that meeting is to say so while the concrete is still a drawing.