water

Once you’ve reasonably developed the high-level requirements for your design, it’s time to whip out as many requirements as you can. As one of the major concerns following Peak Oil is adequate water supplies, we can start by focusing on water requirements. We’ll also explore a few examples of effective requirements writing.

Let’s start with the following test requirement:
The water system shall provide potable tap water at a temperature suitable for drinking.

This requirement has the right idea, but how do we define what temperature is suitable for drinking? We could say it will provide “cool” water, but there’s no solid definition for this. According to the Association of Home Appliance Manufacturers cold tap water (for appliance purposes) is less than 86 &deg F. There aren’t many solid references on “comfortable” cold tap water, so for now let’s choose (by intuition) 50 &deg F for the lower end of cold tap water temperature range.