As per ZDHC SAP V2.1, ZDHC Approved Sampling Personnel can collect separate samples by hand for no less than 6 hours, with no more than 1 hour between separate samples. That means the sampler should collect no less than 7 samples and each separate sample shall be of equal volume and combined to produce 1 composite sample. The composite sample container must be cooled at 4 degrees Celsius during sampling.