ASTM D4801

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Author Message James W. Kraus (Unregistered Guest) Unregistered guest Posted on Wednesday, May 03, 2017 - 10:46 am:    Hi all - I had a question about ASTM D4801 (Standard Specification for Polyethylene Sheeting in Thickness of 0.25mm (0.010 in.) and Greater) that I am hoping someone can help me with. Section 7.5 (Dimensions) of the standard says that the sheeting shall be supplied in the length, width, thickness specified between the user and supplier, except that it is permissible for 4% of the sheet in a shipment to be trimmed 2 inches undersized or half-size. I don't get the last part. Why is it permissible for a supplier to send undersized sheeting? Does anyone know the reason for this caveat? Also, what does "or half-size" mean? Thanks in advance for your feedback. Wayne Yancey Senior Member Username: wayne_yancey Post Number: 815 Registered: 01-2008 Posted on Wednesday, May 03, 2017 - 11:01 am:    My purely scientific wild ass guess is the as-fabricated rolls may be cut in half for whatever reason. Two 5 foot rolls from a 10 foot roll and so on. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1712 Registered: 03-2002 Posted on Thursday, May 04, 2017 - 12:19 pm:    It most likely has to do with the manufacturing process and how closely they can hold tolerances. For construction, this probably won't matter. Also, one important point to remember about this type of requirement in a standard is that the designer/architect/specifier is not going to make any requirements about the roll size, only the thickness and other physical characteristics. The contractor/subcontractor will determine what roll size and width to purchase. It may even be more restricted than that (I don't have the standard to look at): only the manufacturer's sale to the distributor may be intended.