To add to George's comments:
Relevant section in SQF Code 11.6.1 Cold Storage, Freezing and Chilling of Foods
18.104.22.168 ...shall be designed and constructed to allow for the hygienic and efficient refrigeration of food
22.214.171.124 Sufficient refrigeration capacity shall be available to chill, freeze, store chilled or store frozen the maximum anticipated throughput of product
One additional thing to consider to bear in mind is capability to maintain temperatures at maximum ambient temperatures under normal operating conditions such as during and after unloading/loading.
Normally validation would involve gaining evidence that the temperatures you operate at are conducive to food safety (for example reference to legislation or scientific information or in house studies proving product is safe after storing at your prescribed conditions).
Secondly validation that the product is maintained at the correct temperature under the prescribed storage controls (Re. multi-point probe in product in warmest part of store). Such validation evidence is not required regularly but would need to be re-validated in the event of changes that could possible affect the product. In the event of no changes this evidence could be reviewed as part of an annual Food Safety Plan review and a decision made as to whether it needs to be revisited (See reference to Food Safety Plan below).
In the Guidance for SQF Implementation Edition 7.1 – Module 11 there are prescribed temperatures although there is also reference to considering legislation.
11.6.1 Implementation Guidance (page 49)
Refrigeration equipment shall have the capacity to maintain an ambient temperature at or below 5°C (40°F) except when loading or unloading product from the cooler unless other temperatures are prescribed by legislation. During these operations, the ambient temperature must return to 5°C (40°F) within a short time after access doors are closed.
Freezing and cold storage equipment shall have the capacity to maintain a product temperature below -15°C (5°F) and must be maintained during loading and unloading.
Monitoring and validation of the cooler temperature shall be done in accordance with the site’s Food Safety Plan or similar document.
The site shall be able to verify and validate cooling or storage temperatures prescribed by legislation.
11.6.1 Auditing Guidance (page 50)
Cold storage, freezing, and chilling procedures (SOPs) and temperature validation procedures will be reviewed as part of the initial desk audit.
Subsequently, they will be audited as part of each facility audit through observation, review of records and interviews with refrigeration mechanics and operating personnel.
SQF does seem to confuse when considering a traditional definition of validation but at least does give 'validation' evidence examples, these include (refer to page in guidance for full list):
SOPs exist for chilling, freezing and cold storage
SOPs exist for validation of chilled and frozen temperatures and times
Supplier can confirm the effective operation of the chillers/freezers
Supplier can confirm the effective operation of the chilled and cold storage rooms
Cold storage rooms are properly designed and constructed
Cold storage rooms are easily cleaned