1 Scope
NOTE This standard covers hydronic radiant heating and cooling panels that transfer heat predominantly by radiation, supplemented by natural convection, without forced air movement through the panel itself. (1.1)
NOTE The following panel families are covered: prefabricated metal radiant ceiling panels, concealed above-drywall radiant ceiling panels, in-floor hydronic radiant systems, thermally active building surfaces, and wall radiant panels. (1.2)
NOTE Applications include offices, laboratories, healthcare facilities, hospitality, and mixed-use spaces where low-noise, draft-free, high-comfort sensible conditioning is the design intent. (1.3)
NOTE Radiant panels provide sensible-only conditioning and remove no latent load. (1.4)
1.5A cooling installation shall be paired with a dedicated outdoor air system (DOAS) or other dehumidification source that conditions ventilation air to a dew point below the panel surface temperature.
1.6The means of ventilation-air dehumidification is a system-level coordination requirement that shall be confirmed before radiant cooling capacity is finalized.
NOTE Hydronic radiant panels are distinguished from chilled beams by their heat transfer mechanism. (1.7)
NOTE Radiant panels transfer heat chiefly by radiant exchange between the panel surface and the surrounding surfaces and occupants, with the panel itself moving no air. (1.7.1)
NOTE Active chilled beams are induction devices that use ducted primary air to induce room air across a coil and are convection-dominant; if the dominant mechanism is inductive convection, the device is a chilled beam and is outside this standard. (1.7.2)
NOTE Radiant panels and chilled beams shall not be combined in a single specification section, because doing so produces bidding confusion and incorrect submittals. (1.7.3)
NOTE The following are excluded and are governed by the standards named: hydronic supply and return distribution piping, headers, risers, mains, and pipe insulation (
Hydronic Piping); fan-coil and fan-driven terminal units (
Fan Coil Units,
Terminal Heating Units); cabinet and horizontal unit heaters (
Unit Heaters); heating and cooling coils within air-handling units (
Heating And Cooling Coils); and domestic hot water heating and storage (
Plumbing Equipment).
(1.8) NOTE Electric radiant heating panels and electric resistance floor mats with no hydronic circuit are outside this standard's scope. (1.9)
NOTE Central hydronic plant equipment - chillers, boilers, and cooling towers - is outside this standard's scope. (1.10)
2 Referenced Standards
2.1Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
| Standard |
Title |
| ANSI/ASHRAE 138-2021 |
Method of Testing for Rating Ceiling Panels for Sensible Heating and Cooling |
| ASHRAE Handbook |
HVAC Systems and Equipment, Chapter 6 - Radiant Heating and Cooling |
| ASHRAE 55-2023 |
Thermal Environmental Conditions for Human Occupancy |
| ASHRAE 90.1-2022 |
Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings |
| ISO 18566 |
Building Environment Design - Hydronic Radiant Heating and Cooling Panel Systems (Parts 1-4) |
| ISO 11855 |
Building Environment Design - Embedded Radiant Heating and Cooling Systems (Parts 1-6) |
| ASTM B88 |
Standard Specification for Seamless Copper Water Tube |
| ASTM F876 |
Standard Specification for Crosslinked Polyethylene (PEX) Tubing |
| ASTM F877 |
Standard Specification for Crosslinked Polyethylene (PEX) Plastic Hot- and Cold-Water Distribution Systems |
| NFPA 13 |
Standard for the Installation of Sprinkler Systems |
| NFPA 13R |
Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies |
| IMC |
International Mechanical Code, Chapter 14 - Hydronic Piping |
NOTE ANSI/ASHRAE 138-2021 is the currently active US test and rating standard for ceiling radiant panels and supersedes the 2013 (R2016) edition; panel capacity ratings shall be reported on that basis. (2.3)
NOTE ISO 18566 applies to prefabricated panel systems with an open air gap, while ISO 11855 applies to embedded systems with no air gap (in-slab, TABS, and in-floor); the applicable series depends on the panel family selected. (2.4)
3 Submittals
3.1 Action Submittals
3.1.1The Contractor shall submit the following action submittals for review before fabrication or ordering:
- Product data for each panel type, including room-side sensible capacity ratings reported per ANSI/ASHRAE 138, water temperature and flow basis, and pressure rating.
- Shop drawings showing panel layout, coverage percentage, module dimensions, manifold and circuit arrangement, and coordination with lighting, diffusers, sprinklers, and structure.
- Hydronic circuit diagram showing supply/return connections, balancing devices, isolation valves, air vents, and zone control valves.
- Controls sequence of operation including dew-point protection interlock and supply water reset logic.
- Water quality and chemical treatment plan, including inhibitor/glycol formulation and aluminum compatibility confirmation where aluminum panels are used.
- Structural attachment and seismic restraint details for suspended panels.
☑ Product data with ASHRAE 138 room-side capacity ratings
☑ Panel layout and coverage shop drawings
☑ Hydronic circuit and manifold diagram
☑ Controls sequence of operation (dew-point interlock)
☐ Water quality and chemical treatment plan
☐ Structural attachment and seismic restraint details
3.2.1The Contractor shall submit the following informational submittals:
- Manufacturer factory hydrostatic test certificates for panels or manifold assemblies.
- Field pressure test reports for installed circuits.
- Balancing report listing design and measured flow at each circuit or manifold.
- Commissioning records including dew-point interlock functional test and flush/fill water quality verification.
☑ Factory hydrostatic test certificates
☑ Field pressure test reports
☑ Balancing report (design vs. measured flow)
☑ Commissioning records and dew-point functional test
3.3 Closeout Submittals
3.3.1The Contractor shall submit the following closeout submittals:
- Operation and maintenance manuals for panels, manifolds, control valves, and dew-point sensors.
- As-built drawings showing final panel and circuit locations and manifold zoning.
- Warranty documentation for panels and embedded tubing.
☑ Operation and maintenance manuals
☑ As-built drawings (panel and circuit locations)
☑ Warranty documentation
4 Quality Assurance
4.1Panels shall be the product of a manufacturer regularly engaged in the production of hydronic radiant panels for not less than five years.
4.2Ceiling panel capacity ratings shall be established by test in accordance with ANSI/ASHRAE 138 and reported as room-side sensible capacity.
NOTE Room-side capacity is the radiant plus convective heat exchange delivered to the occupied space; it excludes heat the panel exchanges with the ceiling plenum. (4.3)
NOTE Sizing cooling capacity from water-side panel capacity overstates useful room cooling by 10 to 25 percent, because the panel also draws heat from the plenum above it. (4.3.1)
4.5The installing contractor shall employ personnel trained by the panel or embedded-tubing manufacturer for the system type being installed.
4.6A single manufacturer shall furnish each panel system and its manifolds as a coordinated assembly to maintain warranty and performance accountability.
5 Environmental and Service Conditions
NOTE Radiant panels condition the occupied zone through mean radiant temperature, so design targets shall be expressed in operative temperature, not air temperature alone. (5.1)
NOTE Operative temperature combines air temperature and mean radiant temperature; radiant systems shift comfort by changing surface temperatures, allowing equal comfort at slightly different air temperatures. (5.1.1)
5.2The design operative temperature shall fall within the comfort zone of ASHRAE 55 for the project's clothing and metabolic assumptions.
5.4Floor surface temperature in perimeter and bathroom zones may reach 95°F (35°C) where occupants do not dwell.
5.5Cooling panel surface temperature shall be maintained above the space dew-point temperature at all times to prevent surface condensation.
NOTE Maintaining the panel surface above dew point is the single most critical design and control requirement for radiant cooling; condensation causes staining, mold, and substrate damage. (5.6)
5.7The hydronic system serving the panels shall be a closed loop with controlled water quality to limit corrosion and oxygen ingress.
5.8Aluminum panels shall use an aluminum-compatible inhibited fluid; the loop pH shall be held between 7.0 and 8.5 for aluminum heat plates.
NOTE Standard HVAC glycol blends with high-pH inhibitor packages (pH above 9.0) corrode aluminum heat plates; an aluminum-compatible inhibited glycol shall be specified where aluminum panels are used. (5.8.1)
6 Panel Type and Configuration
6.1The panel family shall be selected to match the heat transfer surface, mounting method, and architectural integration required by the space.
● Prefabricated metal radiant ceiling panel (suspended or lay-in grid)
○ Concealed above-drywall radiant ceiling panel
○ In-floor hydronic radiant (thin-slab or below-subfloor)
○ Thermally active building surface (TABS, embedded in structural slab)
○ Wall radiant panel
NOTE Prefabricated metal radiant ceiling panels are aluminum or steel tube-and-plate units mounted in a suspended or lay-in grid, available in standard module widths of 12 in and 24 in and lengths from 2 ft to 8 ft. (6.2)
NOTE Concealed above-drywall panels place aluminum omega-channel heat plates and PEX tubing above 5/8 in drywall so no panel is visible at the ceiling. (6.3)
NOTE In-floor systems embed PEX-a or PEX-b tubing in a thin lightweight concrete or gypsum topping (typically 1.5 in to 2 in) or below the subfloor with aluminum heat transfer plates. (6.4)
NOTE Thermally active building surfaces embed PEX or copper in the structural concrete slab (typically 4 in to 8 in) and are engineered per project; ISO 11855 governs their design. (6.5)
NOTE Wall radiant panels are vertical aluminum panels with a copper or PEX circuit, typically used for perimeter supplemental heating. (6.6)
6.7 Heat Transfer Surface
6.7.1The heat transfer surface material shall be selected for compatibility with the loop fluid and the required capacity.
● Aluminum plate with bonded PEX
○ Steel plate with welded steel tubes
○ Copper tube-and-plate
○ Gypsum-encapsulated PEX
6.7.2Embedded tubing shall conform to ASTM F876 and ASTM F877 for PEX or ASTM B88 for copper.
6.7.3PEX used in embedded floor and ceiling circuits shall include an oxygen-diffusion barrier where the loop contains ferrous components, to limit oxygen ingress and corrosion.
6.8 Ceiling Integration Method
6.8.1The ceiling integration method shall be coordinated with the architectural reflected ceiling plan.
● Exposed panel in suspended grid
○ Concealed above drywall
○ Modular snap-in acoustic tile
6.8.2Panel finish shall be factory-applied; white is the standard finish and custom colors shall be confirmed for emissivity and capacity impact.
Factory-painted white (standard)
Factory-painted custom color
Field-painted
NOTE Custom and field-applied finishes shall not reduce surface emissivity below the value used to establish the rated capacity. (6.8.3)
7 Operating Mode and Water Temperatures
7.1The operating mode shall be selected to match the loads the panels are intended to serve.
○ Heating only
○ Cooling only
● Dual-mode heating and cooling (4-pipe)
7.2Cooling supply water temperature shall be set above the space dew-point temperature with a minimum margin of 2°F to 3°F.
NOTE A cooling supply water temperature that is too low for the prevailing space dew point will cause condensation regardless of any downstream control; the design value is the first line of dew-point defense. (7.3)
7.4Heating supply water temperature for ceiling and wall panels shall be selected for the design heating capacity within the panel pressure and temperature rating.
7.5Heating supply water temperature for in-floor systems shall be limited so the floor surface temperature stays within the occupied-zone limit.
7.6Design flow rate shall be established per manufacturer data for each panel module and confirmed against the available pump head.
0.30.8
Default: 0.5 GPM per 100 ft²
8 Capacity and Coverage
8.1Panel quantity shall be derived from the room-side capacity rating and the design sensible load, after deducting all ceiling or floor obstructions.
8.2Ceiling panel cooling capacity shall be taken from the room-side rating; typical open-plan office values fall in the range of 8 to 20 Btu/h·ft².
8.3Ceiling panel heating capacity at 120°F supply typically falls in the range of 20 to 50 Btu/h·ft².
2050
Default: 30 Btu/h·ft²
8.4In-floor heating capacity typically falls in the range of 8 to 16 Btu/h·ft², limited by the floor surface temperature ceiling.
8.5Panel coverage shall be specified as a percentage of conditioned ceiling or floor area and shall account for lighting, diffusers, and structural obstructions.
NOTE Specifying coverage without modeling obstructions is a common error; actual installed coverage is commonly 15 to 25 percent less than the design assumption when lighting, diffusers, and structure are accounted for. (8.6)
8.7Coverage shall be modeled against the reflected ceiling plan before the panel quantity is fixed, so that obstructions do not leave the space short of capacity.
NOTE In-floor systems shall confirm the maximum finish-floor R-value, because carpet, wood, or thick coverings reduce effective output and can overheat the slab. (8.8)
8.9Finish-floor covering over an in-floor radiant system shall not exceed R-1.0 for cooling service or R-2.0 for heating service.
0.52
Default: 1 h·ft²·°F/Btu
9 Controls and Dew-Point Protection
NOTE The control system shall maintain the panel surface above the space dew point under all operating conditions while delivering the design operative temperature. (9.1)
9.2A dew-point protection method shall be provided for every cooling installation.
● Space dew-point sensor with chilled water shutoff
○ Supply water temperature reset on space dew point
○ Dedicated DOAS pre-dehumidification upstream
NOTE A dedicated DOAS or equivalent dehumidification source shall condition ventilation air below the panel surface temperature; without it, condensation on cooling panels is unavoidable in humid climates. (9.3)
9.4The controls sequence shall raise the cooling supply water temperature or close the chilled water supply when the space dew point approaches the panel surface temperature.
NOTE The dew-point interlock shall be a functional, tested element of the sequence of operation and not merely a setpoint note. (9.5)
9.6The control valve and pipe configuration shall be selected to match the operating mode and the dew-point control strategy.
○ 2-pipe with 2-way control valve
○ 2-pipe with 3-way control valve
● 4-pipe with 2-way control valves
9.7Manifold zoning shall group panels so each zone can be controlled and balanced independently.
○ Individual room manifold
● Zone manifold serving multiple panels
9.8Energy performance, including pipe insulation, control setpoints, and reset, shall comply with ASHRAE 90.1.
10 Balancing
10.1Each panel circuit or zone manifold shall be provided with a means of flow balancing so that surface temperatures are uniform across the conditioned area.
● Pressure-independent control valve (PICV) at each zone manifold
○ Manual balancing valve at each panel circuit
NOTE Pressure-independent control valves should be provided at each zone manifold so that panel flow balance is not disrupted when zone valves elsewhere in the system modulate. (10.2)
NOTE Omitting pressure-independent balancing causes flow at one zone to shift when other zone valves open or close, producing uneven surface temperatures and comfort complaints. (10.2.1)
10.3The system shall be balanced to the design flow at each circuit, and measured flows shall be recorded in the balancing report.
11 Sprinkler and Trade Coordination
NOTE Suspended radiant ceiling panels shall be coordinated with the fire sprinkler layout, because panels can obstruct standard sprinkler coverage. (11.1)
11.2Panel layout shall be coordinated with the sprinkler contractor early enough to add heads or apply listed obstructed-coverage rules under NFPA 13 or NFPA 13R as required.
11.3Where panels obstruct sprinkler discharge, additional heads or listed obstructed-coverage sprinklers shall be provided as required by NFPA 13.
11.4Panel layout shall be coordinated with lighting, diffusers, access panels, and structural elements so that the installed coverage meets the modeled coverage.
12 Testing
12.1Each panel or manifold assembly shall be factory hydrostatically tested at 1.5 times the working pressure, with a minimum test of 200 psi for 150 psi rated systems, held for not less than 15 minutes with no leakage.
12.2Maximum working pressure for standard prefabricated panels is 150 psi (10 bar); the panel rating shall be verified against the project hydronic system design pressure.
12.3After installation, each circuit shall be field pressure tested at not less than 1.5 times the design working pressure for a minimum of 2 hours with no pressure loss, per the IMC and manufacturer requirements.
12.4Embedded tubing shall be held under test pressure during placement of any topping slab so that damage during the pour is detected immediately.
12.5A functional test of the dew-point protection interlock shall be performed during commissioning to confirm the panel surface is held above dew point.
13 Installation
13.1Panels shall be installed level and in plane with the finished ceiling or floor, with module joints aligned per the approved shop drawings.
13.2Suspended panels shall be independently supported from the structure and shall not transfer load to the ceiling grid beyond the grid's rated capacity.
13.3Suspended panels shall be seismically restrained where required by the adopted building code for the project's seismic design category.
13.4Embedded tubing shall be secured against flotation and displacement before any topping or concrete is placed.
13.5In-floor tubing shall maintain the design spacing and shall not be kinked or reduced in bore during installation.
NOTE Connections to the hydronic distribution shall be made with isolation valves and unions or flanges so that panels and manifolds can be removed for service. (13.6)
NOTE Supply and return connections, balancing, and isolation devices shall be coordinated with the distribution piping standard
Hydronic Piping.
(13.6.1) 13.7Air vents shall be provided at system high points and at each manifold so that the panels can be fully purged of air.
13.8The system shall be flushed to remove construction debris and flux residue before the panels are placed in service.
NOTE Construction debris, flux residue, and oxygen ingress cause early corrosion in aluminum panels; pre-flush, fill water quality, and chemical treatment shall be completed before commissioning. (13.9)
13.10The fill water and chemical treatment shall meet the approved water quality plan before the panels are charged.
14 Delivery, Storage, and Handling
14.1Panels shall be delivered in the manufacturer's packaging with end caps or plugs on tube connections to keep internal surfaces clean and dry.
14.2Panels shall be stored flat and protected from moisture, dust, and physical damage until installation.
14.3Panel finishes shall be protected from overspray, adhesives, and abrasion during the work of other trades.
14.4Embedded tubing shall be protected from ultraviolet exposure and sustained sunlight during storage where the product is UV-sensitive.
15 Warranty
15.1The manufacturer shall warrant panels and embedded tubing against defects in materials and workmanship for a minimum of two years from substantial completion.
1 year
2 years
5 years
10 years
15.2Embedded tubing shall carry the longer warranty period offered for the tubing product, because it is not accessible for replacement after the slab is placed.
16 Spare Parts
16.1The Contractor shall furnish spare dew-point sensors and control valve actuators of each type installed, in the quantities scheduled.
☑ Spare dew-point sensor(s)
☑ Spare control valve actuator(s)
☐ Spare manifold air vent(s)
☐ Touch-up finish for panels
16.2Touch-up finish matching the factory panel finish shall be provided for field repair of minor surface damage.