Atmospheric Monitoring Frequency…Update for Roco Students
One of our very attentive students recently noticed a statement in our Study Guide that was incorrectly attributed to OSHA when it is really a Roco Best Practices Guideline. In the Confined Space chapter of our Study Guide, it states that OSHA requires air monitoring “within 30 minutes of the entry,” and this is not an OSHA requirement. The 30-minute timeline is a Roco recommendation for conducting “baseline” pre-testing prior to entry, but it is not an OSHA requirement.
The revised wording is explained below. You may click here to download and print the corrected pages for your Roco Study Guide. If you have any questions or need assistance, please contact the Roco office at 800-647-7626.
CONFINED SPACE CHAPTER
(1) ATMOSPHERIC MONITORING: (Page 13)
ROCO RECOMMENDATION: Although OSHA does not define a specific timeline to conduct pre-entry atmospheric monitoring, we recommend that a “baseline test” be conducted approximately 30 minutes prior to the entry and then another test conducted immediately prior to entry. A comparison of these readings could indicate that atmospheric changes have occurred inside the space. If a space has been vacated for a period of time, it is recommended that similar baseline testing be repeated.
Also, while OSHA allows for periodic monitoring and sets no exact timespan between testing, Roco recommends continuous air monitoring any time workers are in the space. In addition, pre-entry testing as well as periodic testing should be based on the hazard assessment for a given space to include any previous work activities that may have introduced atmospheric hazards as well as any known history of hazardous atmospheric conditions. Another consideration is how rapidly those hazards can change the atmosphere, which may require additional precautions for safe entry.
(2) MONITORING FREQUENCY: (Page 15)
OSHA does not define a specific timeline for conducting pre-entry atmospheric monitoring or periodic testing. OSHA 1910.146 (c)(5) refers to testing the internal atmosphere before an employee enters the space and testing as necessary to maintain acceptable entry conditions. Testing should be based on the hazard assessment for a given space as well as how rapidly those hazards could cause a change in the atmosphere, which may require additional action for safe entry.
As a safer way, Roco recommends continuous monitoring while employees are inside a permit-required confined space.
Frequently Asked Questions: PRCS Standard Clarification (OSHA.gov)
How much periodic testing is required?
The frequency of testing depends on the nature of the permit space and the results of the initial testing performed under paragraph (c)(5)(ii)(c). The requirement in paragraph (c)(5)(ii)(F) for periodic testing as necessary to ensure the space is maintained within the limits of the acceptable entry conditions is critical. OSHA believes that all permit space atmospheres are dynamic due to variables such as temperature, pressure, physical characteristics of the material posing the atmospheric hazard, variable efficiency of ventilation equipment and air delivery system, etc. The employer will have to determine and document on an individual permit space basis what the frequency of testing will be and under what conditions the verification testing will be done.
What does testing or monitoring "as necessary" mean as required by 1910.146(d)(5)(ii) to decide if the acceptable entry conditions are being maintained?
The standard does not have specific frequency rates because of the performance oriented nature of the standard and the unique hazards of each permit space. However, there will always be, to some degree, testing or monitoring during entry operations which is reflective of the atmospheric hazard. The employer must determine the degree and the frequency of testing or monitoring. Some of the factors that affect frequency are:
* Results of test allowing entry.
* The regularity of entry (daily, weekly, or monthly).
* The uniformity of the permit space (the extent to which the configuration, use, and contents vary).
* The documented history of previous monitoring activities.
* Knowledge of the hazards which affect the permit space as well as the historical experience gained from monitoring results of previous entries.
Knowledge and recorded data gained from successive entries (such as ventilation required to maintain acceptable entry conditions) may be used to document changes in the frequency of monitoring.OSHA 1910.146 REFERENCES
Before an employee enters the space, the internal atmosphere shall be tested, with a calibrated direct-reading instrument, for oxygen content, for flammable gases and vapors, and for potential toxic air contaminants, in that order. Any employee, who enters the space, or that employee's authorized representative, shall be provided an opportunity to observe the pre-entry testing required by this paragraph.
The atmosphere within the space shall be periodically tested as necessary to ensure that the continuous forced air ventilation is preventing the accumulation of a hazardous atmosphere. Any employee, who enters the space, or that employee's authorized representative, shall be provided with an opportunity to observe the periodic testing required by this paragraph.
Test conditions in the permit space to determine if acceptable entry conditions exist before entry is authorized to begin, except that, if isolation of the space is infeasible because the space is large or is part of a continuous system (such as a sewer), pre-entry testing shall be performed to the extent feasible before entry is authorized and, if entry is authorized, entry conditions shall be continuously monitored in the areas where authorized entrants are working;
Test or monitor the permit space as necessary to determine if acceptable entry conditions are being maintained during the course of entry operations;