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hygein_article.docxClearing The Air on Respiratory Cartridge Change-Outs Natural human senses can only go so far in keeping us safe.
November/December 2016 Think about it. In our homes, we rely on smoke detectors to help keep us safe from smoke and fire that we may not otherwise detect. Carbon-monoxide detectors also help protect us against a tasteless and odorless gas. It’s the same case with our cars. Our ability to see traffic, hear warning sounds and feel driving conditions can only go so far. Newer safety technologies, such as blind-spot detection, rearview cameras and forward-collision warning, complement our human senses to help make us more alert drivers. Considering these many ways in which technology helps keep us safe in our personal lives, it’s surprising that some people exposed to gases and vapors in the workplace might rely on their human senses to know when to change their respirator cartridge. Countries such as the U.S., Canada and Australia do not allow odor thresholds to be used as a primary indicator for changing gas or vapor cartridges. Instead they have regulations in place that require employers to establish a respirator cartridge change-out schedule. Unfortunately, some employers either aren’t familiar with or don’t fully understand the regulatory requirements. This puts the burden on employees to determine when to change their cartridges, which too often comes in the form of a rudimentary smell test. In other instances, a change-out schedule may be in place, but it doesn’t accurately reflect the varying exposure patterns of each individual worker. As a result, some employees may wear their cartridges longer than they should. They also may incur safety issues by relying on their own senses versus the change-out schedule. Other employees may change their cartridges too soon, which can be wasteful.
Proper understanding of when to replace cartridges can help companies reduce the potential for safety incidents, improve compliance and maximize equipment investments. Getting Up to Standard For those not familiar with respiratory cartridge change-out requirements or unsure if they are in compliance, the best place to begin is with the standard itself. U.S. OSHA standard 29 CFR 1910.134 requires employers to develop a cartridge change-out schedule based on objective information to ensure cartridges are changed before the end of their service life. According to OSHA, information used to determine a change-out schedule includes “the exposure assessment and information based on breakthrough test data, mathematically based estimates and/or reliable use recommendations from the employer’s respirator and/or chemical suppliers.” 1 A proper exposure assessment is absolutely critical because a number of different factors can affect a cartridge’s service life. This can include specific gases or vapors, exposure levels, breathing rates, temperature, humidity, cartridge capacity and storage/re-use patterns. Furthermore, OSHA suggests that employers apply a safety factor – which is a reduction to an estimated service life – to account for workplace variables.2 With this information in hand, a change-out schedule can be developed. Beyond defining timelines, OSHA requires that employers include “the information and data relied upon, the basis for the canister and cartridge change schedule, and the basis for reliance on the data” in their change-out programs.3 Those needing help in creating their change-out schedules can turn to service-life calculators available from respiratory equipment manufacturers. The calculators use the exposure-monitoring information and specific cartridge product information to produce a service-life estimate. They are free to use and take mere minutes to complete. A New Cartridge Alternative Respirator cartridges with end-of-service-life indicators (ESLI) can supplement or in some environments serve as the primary cartridge change-out method. Cartridges with an ESLI are already used for certain chemical exposures, such as mercury vapor or carbon monoxide. They comply with the OSHA standard so long as the ESLI is compliant with National Institute for Occupational Safety and Health (NIOSH) requirements. In addition, an ESLI is now available for workplaces with certain organic vapors above certain concentrations. This ESLI uses an indicator bar located inside the cartridge to track exposure and monitor a cartridge’s service life. The ESLI absorbs organic vapors as they travel through the cartridge, which above certain concentrations results in a visible growth of the indicator bar. The indicator can be used as a primary changeout method or as a backup method, depending on the environment; if the indicator bar reaches the end-of-service line, the user knows it’s time to change the cartridge. Using an ESLI for determining cartridge change can help optimize the change-out process for each worker. A change-out schedule is often broadly applied to a group of workers and, therefore, not reflective of the unique use, storage and re-use conditions for each worker. An ESLI, on the other hand, can provide individual indication based on the variables specific to each worker, such as breathing rate, exposure level and any changes that might occur in temperature and humidity. At a personal level, an ESLI can give workers greater ownership of their own health and increased confidence in their protection equipment. More broadly, it can help ensure workers aren’t using cartridges beyond their service lives or discarding them too soon. Case in point: ENTEK, a leading supplier of lead-acid separators, lithium-ion separators, extruders, and engineering services for the battery and extrusion markets, recently had some of its workers use an ESLI. The EHS and HR manager found the results of the trial eye-opening. In Newcastle-upon-Tyne, United Kingdom, the company produces membranes for car batteries. At this production site, workers previously used a system in which they changed their cartridges on a pre-defined schedule. But the system was difficult to monitor, and some workers discarded their cartridges (referred to as filters in the UK) at different rates. They agreed to a four-month trial of using an ESLI. “Being able to monitor how much life the filter has left is a big bonus from a health and safety point of view,” said Andy Rennie, the EHS and HR manager at ENTEK. “It helps me to ensure that the filters do not reach the point where vapors start to breakthrough, exposing my staff to potential harm.” For some organic vapors or exposure levels, this new ESLI may not be appropriate as the primary method for determining a cartridge change schedule. But the ESLI cartridges also can be used as a backup method for determining cartridge change-out. This could include situations in which organic vapor levels increase and the pre-defined change-out schedule is no longer applicable. Cartridges may be changed according to the normal change schedule or according to the ESLI, whichever occurs first. Empowering Safety Ensuring employees are protected when working around organic vapors and meeting regulatory requirements can be a difficult and complicated undertaking. Fortunately, safety managers and industrial hygienists have more tools and technologies than ever at their disposal to properly define change-out schedules, empower workers and give them greater peace of mind when it comes to their own safety. (Endnotes) 1 U.S. OSHA, Respirator Change Schedules, https://www.osha.gov/SLTC/etools/respiratory/change_ schedule.html 2 U.S. OSHA, Safety Factor, https://www.osha.gov/SLTC/etools/respi ratory/change_schedule.html 3 U.S. OSHA, Regulations (Standards - 29 CFR) Table of Contents, https://www.osha. gov/pls/oshaweb/owadisp.show_document?p_id=12716&p_table=STANDARDS Author Erik Johnson, Technical Service Specialist, 3M Company For more information on respiratory cartridge change-outs, visit
