Hose bibs - permanent irrigation

I suppose "I am asked to provide manufacturers documentation" indicates that you already entered documentation review and this request is from reviewers. In such case there is only one possibility - gain any (semi)official letter from producer/manufacturer stating that "Coefficient of irrigation efficiency can be assessed at...". But it's literally grasp at a straw. If you still can change compliance path, it's preferable to use path "no permanent irrigation". "If I have permanent irrigation system only on a 50% of green surface and the rest has no irrigation" - it's the same project? If yes, variant "no permanent irrigation" is not relevant. In such case I would utilize the same greening area for a baseline and proposed design, and utilize the same areas of watering in both cases - i.e. if half of proposed case greening area is not irrigated, the same area wouldn't be counted as irrigated in a baseline case.