Indoor Pool HVAC + Chloramine Control — ASHRAE Ch 5 + EU REACH + FINA + EN 15288
An Olympic 50 m × 25 m indoor pool needs 16,200 CMH dedicated outdoor air per ASHRAE Ch 5 (3.6 L/s per m² pool surface) — most Indian pools spec 5-8 ACH total without segregated OA, producing chloramine 0.8-1.2 mg/m³ vs the EU 0.3 mg/m³ lifeguard exposure limit. Three failures: 100 % recirculation AHU without dedicated OA, return-air register at ceiling missing dense chloramine at deck level (deck extract at 0.2-0.3 m/s required), heat-recovery dehumidifier omitted (4-5× the OPEX of HRD, < 3 yr payback for the upgrade on 40-60 kg/hr Olympic-pool latent load).
Indoor pool HVAC — why chloramine drives the design
Indoor swimming pools generate trichloramine (NCl3) from chlorine + organic load (sweat, urine, sunscreen). Chloramine off-gasses + accumulates in air, causing asthma + lung damage (lifeguard occupational risk + competitive swimmer + Olympic-pool acquired asthma). ASHRAE Handbook 2023 Ch 5 Indoor Swimming Pools + ASHRAE 62.1-2022 + NFPA 1 + Indian Olympic Association pool specifications + ANSI/APSP-1:2014 (Pool Plumbing) + EN 15288 (European pool design) frame the design. Indian Tier-1 pools — Olympic, hotel, school, hospital therapy — often have 2-3× the chloramine of European pools because air-handling skips 4 critical features.
Olympic 50 m × 25 m pool — HVAC + air-quality design
| Parameter | Value | Standard |
|---|---|---|
| Pool surface area | 1250 m² | dimension |
| Pool air volume (8 m H) | 10,000 m³ | design |
| Pool water temp | 27 ± 1°C (Olympic) | FINA |
| Pool air temp | 29-30°C (1-2°C > water) | ASHRAE Ch 5 |
| Pool air RH | 50-60 % (avoid condensation) | ASHRAE Ch 5 |
| Outdoor air | 3.6 L/s per m² pool surface | ASHRAE 62.1 Table 6-1 |
| Total OA (1250 m²) | 4500 L/s = 16,200 CMH | calc |
| ACH (total air change) | 12-15 | design |
| Trichloramine target | < 0.3 mg/m³ (European Lifeguard limit) | EU REACH + EU Pool |
| Air distribution | top supply + return at deck + chloramine extract at pool surface | ASHRAE |
| Chloramine extract velocity at deck | 0.2-0.3 m/s | design |
| Pool dehumidification | 40-60 kg/hr (latent) | calc |
| Dehumidifier type | heat-recovery dehumidifier | energy efficiency |
| Capex | ₹4.5 Cr | project |
Three Indian indoor pool HVAC failures
- Single 100 % recirculation AHU without dedicated OA — chloramine + humidity build up because recirculated air just dilutes itself. ASHRAE Ch 5 requires dedicated OA at 3.6 L/s/m² pool surface — 16,200 CMH for 1250 m² Olympic pool. Indian designers spec 5-8 ACH total but no segregated OA — chloramine climbs 0.8-1.2 mg/m³ vs 0.3 EU limit.
- Return-air register at ceiling instead of deck — chloramine is denser than air + accumulates at deck level (0-1.5 m). Return registers at ceiling miss the contamination. Specify low-level deck extract at 0.2-0.3 m/s right at pool surface to capture chloramine + relieve at AHU return.
- Heat-recovery dehumidifier missing — Olympic pool produces 40-60 kg/hr latent load. Dehumidification by chiller cooling + reheat is 4-5x the energy of heat-recovery dehumidifier (HRD reclaims latent heat to pool water + space). Capex difference ₹40-60 lakh; OPEX saving ₹18-25 lakh/yr — payback < 3 years.
- ASHRAE Handbook HVAC Applications 2023 Ch 5 — Indoor Swimming Pools.
- ASHRAE 62.1-2022 Table 6.1 — Pool + Spa Ventilation.
- EU REACH + EU Recommendation 2018 — Trichloramine Exposure Limit < 0.5 mg/m³.
- FINA Facilities Rules 2024 — Olympic Swimming Pool Specifications.
- EN 15288-1:2018 + 15288-2:2018 — Swimming Pools Safety Requirements for Design + Operation.
- ANSI/APSP-1:2014 — American National Standard for Public Swimming Pools.
- WHO Guidelines for Safe Recreational Water Environments Vol 2 Swimming Pools 2006.
- SAI India Sports Authority Pool Design Reference 2024.