OAR 437-002-1057
Specified exposure control methods
(1)
Fully and properly implement the engineering controls, work practices, and respiratory protection specified for the task on Table 1, unless you assess and limit the exposure of employees to respirable crystalline silica in accordance with 437-002-1056 (Exposure Assessment).(a)
When construction employees engage in a task identified on Table 1 of this rule, the exposure assessment in 437-002-1056 (Exposure Assessment) is not required when the engineering controls, work practices, and respiratory protection specified are fully and properly implemented for the tasks listed on Table 1 of this rule.(b)
The exposure assessment required by 437-002-1056 (Exposure Assessment) is not required when non-construction employees, such as building maintenance personnel, engage in a construction-like task, which when performed:(A)
Is indistinguishable from a construction task listed on Table 1; and(B)
The task will not be performed regularly in the same environment and condition; and(C)
The engineering controls, work practices, and respiratory protection specified are fully and properly implemented for the task on Table 1 of this rule.(2)
When using wet methods, apply water at flow rates sufficient to minimize the release of visible dust.(3)
For measures that include an enclosed cab or booth, ensure that the enclosed cab or booth:(a)
Is maintained as free as practicable from settled dust;(b)
Has door seals and closing mechanisms that work properly;(c)
Has gaskets and seals that are in good condition and working properly;(d)
Is under positive pressure maintained through continuous delivery of fresh air;(e)
Has intake air that is filtered through a filter that is 95% efficient in the 0.3-10.0 µm range (e.g., MERV-16 or better); and(f)
Has heating and cooling capabilities.(4)
Where an employee performs more than one task in Table 1 during the course of a shift, and the total duration of all tasks combined is more than four hours, the required respiratory protection for each task is the respiratory protection specified for more than four hours per shift. If the total duration of all tasks in Table 1 combined is less than four hours, the required respiratory protection for each task is the respiratory protection specified for less than four hours per shift.
Source:
Rule 437-002-1057 — Specified exposure control methods, https://secure.sos.state.or.us/oard/view.action?ruleNumber=437-002-1057.