Spectator Comfort in Ice Rink Arenas

Overview

Spectator comfort in ice rink arenas presents a unique thermal challenge: occupants must remain comfortable while seated adjacent to a large, cold radiating surface maintained at 15-25°F (-9 to -4°C). The ice surface creates severe radiant asymmetry that cannot be compensated by air temperature alone. Effective design requires understanding radiant heat exchange, metabolic heat production, and clothing insulation to maintain thermal neutrality in the spectator zone.

ASHRAE Standard 55 defines thermal comfort criteria, but ice arena applications require significant adjustments for the radiant deficit created by the ice surface. The mean radiant temperature (MRT) in spectator areas can be 15-25°F below the air temperature, requiring elevated air temperatures or supplemental radiant heating to achieve acceptable thermal conditions.

Radiant Heat Loss to Ice Surface

Spectators experience continuous radiant heat loss to the cold ice surface. The net radiant exchange is governed by the Stefan-Boltzmann law and view factors:

$$q_{rad} = \epsilon \sigma A F_{p-i} (T_s^4 - T_{ice}^4)$$

Where:

• $q_{rad}$ = radiant heat loss (W)
• $\epsilon$ = effective emissivity (typically 0.85-0.95 for clothed occupants)
• $\sigma$ = Stefan-Boltzmann constant (5.67 × 10⁻⁸ W/m²·K⁴)
• $A$ = body surface area (typically 1.8 m² for adult)
• $F_{p-i}$ = view factor between person and ice surface
• $T_s$ = clothing surface temperature (K)
• $T_{ice}$ = ice surface temperature (K)

For a seated spectator facing the ice, the view factor ranges from 0.15 to 0.35 depending on proximity and seating geometry. This results in radiant heat losses of 60-120 W beyond normal room conditions.

graph TB
    subgraph "Spectator Thermal Environment"
        A[Spectator Body<br/>Core Temp: 98.6°F] --> B[Clothing Layer<br/>Surface: 75-80°F]
        B --> C{Heat Exchange<br/>Mechanisms}
        C --> D[Radiant Loss to Ice<br/>60-120 W]
        C --> E[Convection to Air<br/>Variable]
        C --> F[Metabolic Heat<br/>100-120 W seated]

        G[Ice Surface<br/>15-25°F] -.Radiant Exchange<br/>View Factor 0.15-0.35.-> D
        H[Air Temperature<br/>55-68°F] -.Convection.-> E
        I[Radiant Heating<br/>Optional Supplement] -.60-90 W.-> B
    end

    style A fill:#ff9999
    style G fill:#99ccff
    style I fill:#ffcc99

Mean Radiant Temperature Calculation

The mean radiant temperature accounts for all radiating surfaces weighted by view factors:

$$MRT = \sqrt[4]{\sum_{i=1}^{n} F_i T_i^4}$$

In ice arenas, the large cold surface depresses MRT significantly below air temperature. For spectators with direct ice view:

$$MRT \approx T_{air} - (0.4 \text{ to } 0.7) \times (T_{air} - T_{ice})$$

This relationship demonstrates why air temperatures of 55-68°F are required when ice is at 20°F to achieve thermal comfort equivalent to 68-70°F in standard occupied spaces.

Metabolic Heat Production and Clothing Insulation

Sedentary spectators produce approximately 100-120 W (1.0-1.2 met) of metabolic heat. The thermal balance equation:

$$M - W = q_{conv} + q_{rad} + q_{evap}$$

Where:

• $M$ = metabolic rate (W/m²)
• $W$ = external work (zero for seated spectators)
• $q_{conv}$ = convective heat loss
• $q_{rad}$ = radiant heat loss
• $q_{evap}$ = evaporative heat loss

Clothing insulation requirements increase to 1.2-1.5 clo (equivalent to heavy sweater and jacket) compared to 0.5-0.7 clo in standard buildings. Higher insulation values shift more heat loss to the radiant pathway, making radiant asymmetry more problematic.

Heating System Comparison

Design Recommendations

Temperature Setpoints:

• Spectator zone air temperature: 55-65°F (standard seating with expected clothing)
• Premium seating with radiant heating: 50-58°F air temperature
• Concourse and lobby areas: 65-70°F
• Temperature gradient not to exceed 5°F from ankle to head height

Radiant Heating Design: Overhead radiant panels should deliver 25-40 W/m² to spectator areas with direct ice view. Panel surface temperatures of 150-180°F provide comfortable radiant exchange without excessive ceiling temperatures.

Air Distribution:

• Air velocities at head height: <30 fpm to prevent draft sensation
• Displacement ventilation from floor level where feasible
• Vertical temperature stratification controlled through destratification fans
• Humidity maintained at 40-50% RH to prevent condensation while supporting comfort

Radiant Asymmetry Control: Per ASHRAE Standard 55, radiant temperature asymmetry should not exceed 18°F for ceiling-floor differences and 10°F for wall differences. Ice rinks inherently violate these limits, requiring:

• Radiant heating panels positioned to offset ice surface view factors
• Seating orientation minimizing direct ice view where possible
• Higher insulation clothing assumptions (1.2-1.5 clo minimum)

System Separation: Spectator HVAC systems must be completely separated from ice slab refrigeration zones. Independent control prevents:

• Cold air infiltration from ice surface
• Moisture migration causing condensation
• Energy waste from competing heating/cooling loads
• Control instability from thermal coupling

Ventilation and Air Quality

Spectator occupancy densities require 15-20 CFM of outdoor air per person per ASHRAE 62.1. High bay applications benefit from:

• CO₂ demand-controlled ventilation (maintain <1000 ppm)
• Energy recovery on ventilation air (60-70% effectiveness)
• Dedicated outdoor air systems (DOAS) with separate sensible cooling

Commissioning Verification

Thermal comfort verification should include:

• Globe thermometer measurements at seated head height (MRT verification)
• Air velocity mapping at spectator locations
• Surface temperature surveys of radiant panels and ice surface
• Occupant thermal sensation surveys during events
• Infrared thermography of spectator zones

Properly designed spectator comfort systems achieve thermal acceptability ratings above 80% while maintaining ice surface temperatures suitable for skating activities, demonstrating that physics-based design can reconcile competing thermal demands.