Document QgOyQQ2we2N3L44Ly4RZE4O87

5. Squirt-Off. A liquid squirt-bottle containing water was used to wash away brake dust. This was followed by drying off assemblies with a cloth. 6. Vacuum Cleaning. A shop type vacuum cleaner, equipped with a HEPA filter*, was used in combination with compressed air. This system included a brake encapsulation cylinder that completely enclosed the brake-shoe/backing plate assembly. The mechanic operated a com pressed air nozzle fixed inside the enclosure to blow off the brake dust, which was immediately drawn into the vacuum system. A sepa rate vacuum hose was used to vacuum the dust from the brake drums. *HEPA: High Efficiency Particulate Air Filter -99-7% efficiency for 0.3 Pm diameter aerosols. In Methods 1 to 5, and especially 1 to 3, the brake dust has the potential to enter the ambient air of the facility. Conversely, in Method 6 the dust is contained by the HEPA filter which may be removed from the vacuum cleaning system for disposal. 14