What is the annual table top sag tolerance?

• A. 1 mm
• B. 3 mm
• C. 0.5 mm
• D. 2 mm

Answer: (D)

Sag tolerance is the maximum vertical deflection a table top is allowed to experience over time under load. The annual sag tolerance specifically accounts for long-term effects like creep and settling over a year. Two millimeters is a practical middle ground: small enough to keep precision reasonably good, but not so tight that achieving it would require costly, over-engineered construction. A much smaller value would push up cost and stiffness requirements, while a larger value would let noticeable deflection occur during use. So the annual table top sag tolerance is two millimeters.