Question: I am trying to create a declaration using the IPC-1752A standard, but I do not have access to information about the weights of some of the parts. What is the best way to approach this situation? Should I use a “dummy” weight (e.g. 0.01 mg) when I do not know the actual weight?
Answer: No. Using a dummy weight would raise concerns about the validity of your declaration. What’s more, that specific dummy weight may put a substance below threshold when it would not otherwise be based on its true weight. This would lead to inaccurate information being passed through the supply chain.
For IPC-1752A, I recommend using the minimum concentration and maximum concentration in a Class D full material disclosure (FMD) if the actual weight is unknown rather than use a dummy weight. For a Class C declaration, there is no option for minimum or maximum concentration, but mass percentage or concentration could be used to estimate the weight.
Validity is still a concern, but only substances over the threshold would need to be included on the declaration, and having a percentage would more accurately approximate the substance amount present.
Article is current as of 2020-05-01.