The Standard Dump, often abbreviated SD, is the SI unit for fecal volume. Although the Standard Dump will vary from person to person, one Standard Dump is the weighted average of fecal volume eliminated per person per excretion. Standard Dump units are proportional to cubic meters, and can be equated using Sendek's constant.
John: "Man, I really have to take a dump."
Vince: "What is your estimate of oncoming fecal volume, in SI units?"
John: "I would guess around 1.4 Standard Dumps. I ate a lot of pizza last night."