Yes, all estimated uses are based on average use of that situation. For example, it is common to assume 120 gpd per person per US household for domestic use. This doesn't mean someone thinks you drink 120 gpd, nor does it mean you flush 120, nor wash 120 worth of cloths or cars or kids. It is a statistically typical number reflecting what the act of having one typical person in a typical American residence will take out of the reservoir and put into the treamtent plant.
Likewise, the 35 gpd assumes a "typical" factory. I would assume it accounts for a small admin staff, but not a large one, such as an engineering firm would have. Also, a small-to-mid-sized lunch/break room and possibly limited food prep, but no full-scale restaruant. This is why these numbers are NOT for final design, but for rough, initial conservative estimating. You need much more info about the specific plant to pinpoint its flows.
Notice the 35 gpd does not account for any industrial processes. Those will range from nothing to many 1,000s of gallons, and will have to be addressed accordingly (if they are particularly large and/or contaminated, they will require pretreatment).
Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve
