Guide

Airlock, baglock, NPU and route symbols explained

Consistent symbology helps site teams read enclosure plans quickly. This guide explains the common asset categories used in AsbestoPlan and typical enclosure documentation.

Published 2026-06-16 · Planning support only — not compliance advice

Airlocks and baglocks

Airlocks control personnel entry and exit through staged decontamination. Baglocks handle waste material transfer. Position them where the RAMS describes — not where they fit easiest on a copied drawing.

NPUs and DCUs

Negative pressure units maintain enclosure under-pressure. Decontamination units support personnel decon. Show airflow direction where your method requires it.

Routes

Decontamination routes, waste routes and equipment paths should be readable at a glance. Use colour and line style consistently across projects.

Try it on a real layout

Upload or recreate one old enclosure drawing free — Free Preview includes 2 saved projects and watermarked exports.