Mixing Units in Drawings Rejected by Regulators

Don’t let this simple mistake cause your design drawings to be rejected by regulators. 

Modern design drawings often use US Customary and metric units interchangeably. Not a big deal for experienced designers and fabricators that are used to seeing both. However, there are a few specific cases I look for because I’ve seen them rejected by regulators. 

One of those is when 6mm fillet welds are applied to ¼” nozzle reinforcement pads. A 6mm weld works on a 6mm plate. A 6mm weld does not work on a ¼” plate due to the UW-16(d) weld size check. The difference between 6mm and 6.35mm may seem trivial to fabricators but it is not trivial to regulators who check design drawings for this specific combination. 

Did you know that 3rd party reviews help you execute projects faster? Metalmark Engineering checks your design drawings against your design calculations to give you the best chance to sail through regulatory review.