What is the applied leakage test limit for a combination of 2 vehicles?

The applied leakage test limit for a combination of two vehicles is set at -4 psi. This standard is crucial for ensuring the safety and reliability of the vehicles being tested. The negative pressure (or vacuum) indicates the acceptable level of air leakage from the system when it is under testing conditions.

Setting the limit at -4 psi allows for a reasonable margin that accounts for the flexibility and potential wear on the components of the vehicles. It ensures that minor leaks can be tolerated as they do not significantly compromise the overall performance and safety of the vehicles.

In contrast, limits that are set too high could lead to undetected potential issues that might escalate into significant failures, while lower values would be unnecessarily stringent, possibly excluding vehicles that are still fit for service. Maintaining this limit is part of ensuring operational efficiency and safety for emergency response vehicles.