What is the prescribed distance of the vent from the trap seal in plumbing installation?

In plumbing installation, the prescribed distance of the vent from the trap seal is 1.5 meters. This specification is crucial because it ensures that the venting system is effective in maintaining the proper pressure balance within the drainage system while preventing the potential siphoning of water from the trap.

The vent allows air to enter the plumbing system, which helps to equalize pressure and facilitates the smooth flow of wastewater. If the vent is installed too close to the trap seal, there is a risk of creating negative pressure that can pull water out of the trap, leading to a loss of the trap seal and allowing sewer gases to enter the living space. Thus, adhering to the 1.5-meter distance helps in maintaining both efficiency and safety in plumbing operations.

The other distances listed do not align with standard plumbing codes, which is why they are not appropriate choices in ensuring the effectiveness of the venting system.