When do you change respirator cartridges? Change schedules and end-of-service-life indicators
For gases and vapors, a cartridge is changed on a schedule the employer writes down before the job starts, not when the wearer smells something. OSHA requires either a cartridge with an end-of-service-life indicator certified by NIOSH for that contaminant, which is a color window that tells you to change it, or, where no indicator exists for the conditions, a change schedule based on objective data that replaces cartridges before they are used up. The schedule and the data behind it go into the written program. Odor is not accepted as the basis. Particulate filters are different: they do not break through, they load up, and are changed when breathing gets harder, when they are damaged or dirty, or per the manufacturer’s limit in oil mist. In every case, a wearer who notices breakthrough, a change in breathing resistance or a leak leaves the area and the cartridge or filter is replaced before going back.
3M 6001 organic vapor cartridgeOrganic vapor cartridge for 3M 6000 and 7500 series half and full facepiecesWhy not just change it when you smell something? Because by then it has already failed, and for many chemicals it never warns you at all. A cartridge is a bed of activated carbon that holds vapor until it is full; when it is full, the vapor passes straight through at the concentration outside the mask. Some contaminants have no odor at harmful levels, some deaden the sense of smell, and people vary in what they can detect. OSHA removed odor as an acceptable trigger when it rewrote the standard in 1998 and replaced it with the two methods in (d)(3)(iii): a certified indicator, or a schedule based on data.
What does the standard require for gas and vapor cartridges?
Paragraph (d)(3)(iii) gives the employer three choices. One is an atmosphere-supplying respirator, which has no cartridge; the other two are the ESLI and the change schedule.
How is a change schedule set?
OSHA’s guidance lists three ways to estimate how long a cartridge lasts against a given contaminant at a given concentration, and the employer picks one and documents it. Experimental testing: a breakthrough test of the actual cartridge at the workplace concentration, the most reliable method and the one OSHA points to for mixtures. The manufacturer’s recommendation: many makers publish service-life calculators or tables for their cartridges by chemical and concentration; these are specific to the product but may not account for every workplace factor. A mathematical model: NIOSH’s MultiVapor software and similar models estimate breakthrough time from the chemical’s properties, the carbon bed and the airflow, usually for a single contaminant. OSHA’s guidance also warns against the older rule of thumb as the sole basis.
OSHA Respiratory Protection eTool, Change Schedules: experimental tests, manufacturer recommendation, math model; 1910.134(d)(3)(iii)(B)(2): objective information or data.Whatever the method, the schedule is stated in a unit the wearer can follow: change at the start of every shift, every 4 hours of use, after a given number of days, or at a point in a task. It is then cut by a safety factor. OSHA’s guidance names the conditions that shorten service life: work rate (a worker breathing twice as fast pulls twice the contaminant through the cartridge), humidity (water competes for the carbon; above 85 percent OSHA suggests testing), temperature, and concentration. Mixtures are judged on the least well adsorbed compound.
OSHA Respiratory Protection eTool, Change Schedules: factors affecting service life and safety factors.What is an end-of-service-life indicator, and which cartridges have one?
An ESLI is a window on the cartridge that changes color as the sorbent fills. It is a passive, chemical indicator, certified by NIOSH as part of the cartridge approval for a named contaminant. Where a certified ESLI exists for the contaminant and works under the workplace conditions (it must be visible to the wearer and respond at the right level), the employer may rely on it in place of a schedule. ESLIs are approved for only a short list of contaminants; mercury vapor is the common industrial one, and the mercury cartridges in our catalog carry it. For organic vapors in general, there is no NIOSH-certified ESLI on a standard cartridge, which is why most programs run on a change schedule.
1910.134(b), definition of ESLI; 1910.134(d)(3)(iii)(B)(1): ESLI certified by NIOSH for the contaminant; manufacturer approval labels for the cartridges listed below.An ESLI does not remove the wearer’s duty to leave the area on breakthrough, and the respirator still has to be inspected before each use, which includes the cartridge. A cartridge whose window has changed, or whose indicator cannot be read, is replaced.
1910.134(g)(2)(ii)(B); (h)(3)(i)(A) and (h)(3)(ii)(A).When are particulate filters changed?
Particulate filters do not break through the way carbon does; particles stay in the media and the filter gets harder to breathe through as it loads. So the trigger is resistance, damage or hygiene, and the standard’s leave-the-area rule for a change in breathing resistance is the backstop. NIOSH’s filter guidance: N-series filters are used and reused subject only to hygiene, damage and increased breathing resistance; R-series filters used where oil aerosols are present are limited to a single shift or 8 hours; P-series filters in oil follow the manufacturer’s time-use limit. The written program states the rule for each job; on a combination cartridge and filter, whichever element reaches its limit first sets the change.
1910.134(g)(2)(ii)(B); 42 CFR 84.170(a)(2); NIOSH Guide to the Selection and Use of Particulate Respirators (96-101), user notice on N-, R- and P-series service time.What goes in the written program?
- For each contaminant and cartridge: the method used (test, manufacturer calculator, model), the concentration assumed, the humidity and work rate assumed, the computed service life, the safety factor, and the resulting change interval.
- Where an ESLI is relied on: the cartridge part number, the contaminant it is certified for, and the instruction to change at the color change.
- The instruction to leave the area on breakthrough, resistance change or leakage, and that the cartridge is replaced before return.
- Storage of cartridges: sealed in the original packaging until use, since carbon adsorbs vapor from the air whether or not anyone is breathing through it.
- Particulate filter rules by job: shift, resistance, or the 8-hour oil rule.
Cartridges, combination cartridge-filters and ESLI cartridges
28 items · prices liveCartridge type and filter class are as published by the manufacturer. The contaminants each cartridge is approved for are on its NIOSH approval label and the product page; service life depends on the workplace and is set by the employer’s change schedule. Contractor Direct orders ship free.
P100 particulate filters, PAPR cartridges and the facepieces that take them are in the respirator selector.
Questions people ask
How often should respirator cartridges be changed?
On the schedule in the employer’s written program, set from data for the contaminant and concentration, or when a NIOSH-certified ESLI shows end of life. There is no single interval in the standard. (1910.134(d)(3)(iii)(B).)
Can I change the cartridge when I smell the chemical?
No. OSHA does not accept odor or other warning properties as the basis for a change schedule. Smelling it means breakthrough has happened; leave the area and replace the cartridge. (OSHA eTool, Change Schedules; 1910.134(g)(2)(ii)(B).)
What is an ESLI?
An end-of-service-life indicator: a system, usually a color window, that warns the user that the sorbent is approaching saturation. It must be certified by NIOSH for the contaminant. (1910.134(b); (d)(3)(iii)(B)(1).)
Do organic vapor cartridges have an ESLI?
Standard organic vapor cartridges do not carry a NIOSH-certified ESLI, so they run on a change schedule. Mercury vapor cartridges are the common ones that do.
How do I calculate cartridge service life?
Breakthrough testing, the manufacturer’s service-life calculator, or a model such as NIOSH MultiVapor, then apply a safety factor. Document the method and the assumptions in the program. (OSHA eTool, Change Schedules.)
Does humidity affect cartridge life?
Yes. Water vapor competes with organic vapor for the carbon. OSHA’s guidance applies a reduction at 65 percent relative humidity and suggests testing above 85 percent. (OSHA eTool, Change Schedules.)
When do I change a P100 filter?
When breathing resistance increases, when it is damaged or dirty, or per the manufacturer’s limit in oil mist. Particulate filters load up rather than break through. (1910.134(g)(2)(ii)(B); NIOSH 96-101.)
Can an opened cartridge be saved for tomorrow?
Carbon adsorbs vapor from the air whether or not it is being breathed through. Follow the manufacturer’s instructions and the program; many programs count elapsed time from opening, not hours worn.
Standards and ratings on this page are as published in the documents named and by the manufacturers named. The employer’s hazard assessment and written program decide what applies at a given workplace. Verify a rating on the product and its spec sheet before use.