What percentage of vent connector capacity is reduced for every additional 90-degree turn beyond the first two elbows?

In the context of gas venting, the capacity of a vent connector can be significantly affected by the orientation changes, specifically when additional turns such as elbows are added. For every additional 90-degree turn beyond the first two elbows, the vent connector's capacity is generally reduced by 10%. This reduction is crucial for ensuring the safe and efficient operation of a gas system, as it accounts for the increase in resistance to the flow of exhaust gases and can lead to potential issues if not considered.

The rationale behind this percentage is based on factors such as increased turbulence and friction losses that occur when gases navigate through bends in the venting system. By adhering to this guideline, practitioners can maintain appropriate venting conditions, thereby preventing back pressure and ensuring proper functionality of the gas appliance.