Cite Them Right defines it as:

Name of authorising organisation (Year of publication) Number and title of standard. Place of publication: publisher OR Available at: URL (Accessed: date).

(see attached screenshot for italics)

This could also be applied to Summon's Harvard output style which is also deficient. For example, on Summon the Harvard output style cites:
ASTM International 2017, Standard Practice for Sampling Freshly Mixed Concrete. This omits the parentheses around the year, and there is no metadata for: Place of publication: publisher. Similarly, for a BS EN ISO standard, the output is also wonky -- it should display British Standards Institution (2015) before the italics, and there is no place of publication, London (or Chiswick) in this example from Summon: BS EN ISO 9000:2015: Quality management systems. Fundamentals and vocabulary 2015, , British Standards Institute.

I understand this case would not be a simple update to the output style but it would be a useful amendment.