There is no industry standard other than what is in the commentary:
1. Alternate property address. Section 1026.37(a)(6) requires disclosure of the address including the zip code of the property that secures or will secure the transaction. A creditor complies with § 1026.37(a)(6) by disclosing a complete address for purposes of the U.S. Postal Service. If the address is unavailable, a creditor complies with § 1026.37(a)(6) by disclosing the location of such property including a zip code, which is required in all instances. Location of the property under § 1026.37(a)(6) includes location information, such as a lot number. The disclosure of multiple zip codes is permitted if the consumer is investigating home purchase opportunities in multiple zip codes.
You can obtain the address from the loan applicant. Another source, when the loan will be used to purchase the property, is the Purchase Agreement. Assessors' maps may be of help, and Google Maps may also have a street address for the property. Sometimes you'll have to use a lot number for the loan estimate if the assigned street number isn't available until later in the application process, and you can swap in the street number address for the closing disclosure.