What is the maximum relative humidity allowed in a drying oven for SFRM density samples?

The correct answer is 60% relative humidity, as this is the maximum allowed in drying ovens for Spray-Applied Fire-Resistive Material (SFRM) density samples. Maintaining a maximum relative humidity of 60% is crucial because higher levels of humidity can interfere with the drying process of the samples, potentially leading to inaccurate density measurements. If the humidity is too high, it can cause moisture to remain in the samples longer than intended, which might skew the results and lead to unreliable data regarding the SFRM's performance.

This standard helps ensure that the drying conditions are controlled and consistent, which is vital for obtaining precise and reproducible results in fireproofing practices. Therefore, adhering to this maximum humidity level facilitates accurate testing and helps ensure that materials comply with safety regulations and industry standards.