Criterion 6.2.5 Freeze Protection

Criterion text:
1. Protection from freeze damage under the most severe environmental conditions that can be expected in actual use shall be provided for all system components containing heat transfer liquids. The Supplier of each system shall specify the limit (“Freeze Tolerance Limit”) to the system’s tolerance of freezing weather conditions. Systems installed in a location which has no record of an ambient air temperature below 5oC (41oF) may be exempted from the requirements of this paragraph except the specification of a freeze tolerance limit.

2. For systems that rely on manual intervention for freeze protection, the Supplier shall specify the system’s freeze tolerance limit based on exposure for 18 hours to a constant atmospheric temperature. SRCC will evaluate the system design to determine the reasonableness of the specified limit.

3. For solar systems where the collector fluid is water, a minimum of two freeze protection mechanisms shall be provided on each system. Manual intervention (draining, changing valve positions, etc.) is suitable as one mechanism. At least one freeze protection mechanism, in addition to manual intervention, shall be designed to protect components from freeze damage, even in the event of power failure. The thermal mass of a system can be considered to be a limited form of freeze protection.

4. A system in which components and/or piping are subject to damage by freezing shall have the proper fittings, pipe slope and collector design to allow for manual gravity draining and air filling of the affected components and piping. Pipe slope for gravity draining shall have a minimum 2 cm vertical drop for each meter of horizontal length (1/4 inch per foot). This also applies to any header pipes or absorber plate riser tubes internal to the collector.

5. At the time of installation, a conspicuously placed label explaining how the system is protected from freezing and what actions the homeowner should take shall be attached to the system. For systems which rely on manual intervention for freeze protection, this label shall indicate the minimum ambient temperature conditions (Freeze Tolerance Limit) below which owner action is recommended and the procedure to be followed.

Comments:
The SRCC review and certification process has ensured that SRCC certified systems are designed to meet this criterion's freeze protection requirements.

Installers must install the SRCC certified system provided by the manufacturer. The manufacturer and installer must understand what types of systems are valid for use in specific climatic areas.

Each of the above criterion items will be discussed separately below.

Item 1
The manufacturer has specified the freeze limits of the solar system and SRCC has reviewed and certified the system for such. Therefore, logically, the manufacturer would only provide installers solar systems that are suitable for the installers' specific climatic conditions.

The installer in turn must only install those systems that the manufacturer has determined are suitable for their locations. The manufacturer and installer must coordinate the type of system that is procured.

Item 2
SRCC has evaluated the freeze tolerance limit for particular SRCC certified systems.

The installer and manufacturer need to understand the climatic conditions where the certified SRCC systems are being installed. The manufacturer would in turn provide the most suitable system for that geographical area.

Item 3
This requirement stipulates that when the collector fluid is water, a minimum of 2 freeze protection mechanisms shall be provided with the system. The SRCC review process ensures that this is the case. Installers should therefore install the system by following the manufacturer's SRCC approved installation methods and using the manufacturer specified design and components.

Since manual intervention (draining) is one option, the system must be installed in a manner that not only allows proper draining but also includes the valves used in this procedure.

Item 4
The installer must install the certified system in accordance with the manufacturer's SRCC approved installation manual and procedures.

The installer must ensure that for systems in which components or piping are subject to freeze damage, proper collector and piping slope is achieved to allow manual gravity draining. A minimum of 1/4 inch per foot is required for both piping and collector.

Pipe slope is also discussed in Criterion 6.5.15 Pitch or Angle of Piping Installation.

Item 5
A freeze information label, provided by the manufacturer, and affixed to the system by the installer is required. This label describes the basic freeze prevention methods and what actions the owner needs to take.

Figure 1 indicates the information that should be provided in the SRCC freeze information labels.

Figure 1

Installers must use the SRCC certified system that has been approved for their particular location and follow the manufacturer's SRCC approved installation procedures (and schematic).

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