Section C403.3.8—Hydronic coils.
C403.3.8 Hydronic coil selection. Hydronic coils shall comply with Sections C403.3.8.1 and C403.3.8.2.
EXCEPTION: | Replacement coils within existing equipment. |
C403.3.8.1 Chilled-water coil selection. Chilled-water cooling coils shall be selected to provide a 15°F or higher temperature difference between leaving and entering water temperatures and a minimum of 57°F leaving water temperature at design conditions.
EXCEPTIONS: | 1. Chilled-water cooling coils that have an airside pressure drop exceeding 0.70 in. of water when rated at 500 fpm face velocity and dry conditions (no condensation). |
| 2. Individual fan-cooling units with a design supply airflow rate ≤ 5000 cfm. |
| 3. Constant-air-volume systems. |
| 4. Coils selected at the maximum temperature difference allowed by the cooling plant equipment manufacturer's approved operating conditions. |
| 5. Passive coils (no mechanically supplied airflow). |
| 6. Coils with design entering chilled-water temperature ≥ 50°F (10°C). |
| 7. Coils with design entering air dry-bulb temperature ≤ 65°F (18°C). |
C403.3.8.2 Hot-water coil selection. Hot-water heating coils shall be selected to provide a maximum 20°F temperature difference between leaving and entering water temperatures and a maximum of 118°F (48°C) entering water temperature at design conditions.
EXCEPTIONS: | 1. Hot-water heating systems which utilize heat pumps as the primary source. |
| 2. Individual terminal fan units with a design supply airflow rate ≤ 1500 cfm are exempt from the 20°F maximum temperature difference between leaving and entering water temperature requirement. |
| 3. Passive coils (no mechanically supplied airflow). |
| 4. Coils with design leaving air temperature ≥ 95°F (35°C). |
[Statutory Authority: RCW
19.27A.020,
19.27A.025,
19.27A.160 and chapters
19.27A and
19.27 RCW. WSR 22-14-091, 23-12-101, and 23-20-021, § 51-11C-40338, filed 7/1/22, 6/7/23, and 9/25/23, effective 3/15/24.]