Facility Operations & Maintenance Flashcards
7 cards from real NASCO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Facility Operations & Maintenance flashcards as text
What is the recommended free chlorine residual range for a public swimming pool in most US states?
Answer: 1.0–3.0 ppm
Most US health codes require free chlorine between 1.0 and 3.0 ppm to ensure effective disinfection without causing irritation.
Which piece of equipment is primarily responsible for removing suspended particles from pool water?
Answer: Sand or DE filter
Sand, diatomaceous earth (DE), and cartridge filters physically trap suspended particles to clarify pool water.
A pool operator notices foamy water on the pool surface. What is the most likely cause?
Answer: Body oils, lotions, or soaps introduced by swimmers
Foamy water is typically caused by organic contaminants such as body oils, sunscreen, and soaps introduced by bathers.
What is the primary purpose of backwashing a sand filter?
Answer: To remove trapped dirt and debris that restrict flow
Backwashing reverses water flow through the filter to flush out accumulated debris, restoring flow rate and filtration efficiency.
At what pH level does chlorine become LEAST effective as a disinfectant?
Answer: 8.0 or above
As pH rises above 7.8–8.0, hypochlorous acid (the active form of chlorine) converts to the much weaker hypochlorite ion, drastically reducing disinfection.
How often should a pool operator visually inspect drain covers and sumps under normal operating conditions?
Answer: Daily or at each pre-opening inspection
ANSI/APSP standards and the Virginia Graeme Baker Act require daily inspection of drain covers to ensure they are secure and undamaged.
Which chemical is used to RAISE pH in a swimming pool?
Answer: Sodium carbonate (soda ash)
Sodium carbonate (soda ash) is an alkaline compound that raises pool pH when added to the water.