MSA 815181 GMD-P100 Ammonia / P100 Cartridge for Comfo Respirators — Box of 6

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GMD-P100 Overview

The MSA GMD-P100 is a NIOSH-approved combination cartridge that stacks ammonia and methylamine (MA) vapor protection on top of a P100 particulate filter in a single threaded-bayonet unit designed for the MSA Comfo respirator platform — sold as a box of 6 at $227.15 ($37.86 per cartridge). Understanding how combination cartridges differ from single-hazard filters helps clarify why this SKU exists: when your site generates both an alkaline gas and fine dust simultaneously, running separate cartridges is not an option — you need a cartridge that handles both threats in one body. The GMD-P100 fills that gap for MSA full-face Comfo respirators and the Comfo half-mask line. For the broader context of when a P100 pre-filter layer is required, the organic vapor vs. P100 guide explains the hazard-separation logic. MSA part number 815181, GTIN 0641817011072.

Where the GMD-P100 Fits in Respirator Selection

Cartridge selection always starts with hazard confirmation. If your industrial hygienist or SDS identifies ammonia or methylamine above the OSHA PEL but below IDLH concentrations, AND the operation also generates airborne particulate (dust, mist, aerosol), then an air-purifying combination cartridge is appropriate — and the GMD-P100 is MSA's answer for that exact scenario on the Comfo platform. The how-to-choose-a-respirator-cartridge guide walks through the full hazard-identification and APF matching process. The respirator cartridge color chart shows that MSA codes the ammonia/methylamine layer with a green label, consistent with ANSI/ISEA 110 color conventions. If your hazard is pure particulate with no chemical vapor present, a standalone MSA Low-Profile P100 filter is a more economical choice.

Who Should Buy the GMD-P100?

Buy if:

• You already own an MSA Comfo Classic, Comfo II, Ultra-Twin, or Ultra-Elite respirator and need ammonia + particulate protection.
• Your application involves refrigeration systems (R-717 / anhydrous ammonia), livestock or poultry facilities, fertilizer handling, or wastewater treatment where ammonia off-gassing accompanies dust or aerosol.
• Your SDS identifies methylamine as a co-contaminant alongside ammonia — few cartridges specifically list both; the GMD-P100 is NIOSH-approved for both AM and MA service.
• You need a 6-pack to supply a crew and want per-cartridge cost control at ~$37.86 each.

Don't buy if:

• Your hazard includes chlorine, hydrogen chloride, sulfur dioxide, or other acid gases — use the MSA GMB-P100 acid gas + P100 cartridge instead.
• Your hazard includes organic vapors (solvents, hydrocarbons) — the MSA GMA-P100 OV + P100 cartridge covers that profile.
• You need a combination of multiple gas types — the MSA GME-P100 Multi-Gas + P100 cartridge covers OV, acid gas, ammonia/MA, and P100 in one body.
• You use an MSA Advantage series respirator — the Advantage platform uses a snap-on connection and requires Advantage-series filters, not the bayonet-mount GM series.
• Your atmosphere is oxygen-deficient or above IDLH levels — no air-purifying respirator is appropriate; supplied-air or SCBA is required.

What Does the GMD-P100 Protect Against?

The GMD-P100 provides NIOSH-approved protection for the following hazard classes:

What the GMD-P100 Does NOT Protect Against

• Organic vapors (solvents, petroleum distillates, chlorinated hydrocarbons) — no organic vapor sorbent layer
• Acid gases (chlorine, hydrogen chloride, sulfur dioxide, hydrogen fluoride) — no acid-gas sorbent layer
• Mercury vapor — use the MSA Mersorb P100 mercury vapor cartridge
• Radioactive iodine — use the MSA GMI Iodine + P100 cartridge
• Carbon monoxide or other IDLH-level gases
• Odors or nuisance-level vapors outside the designated chemical classes

Best Applications

Refrigeration System Maintenance

Industrial refrigeration using R-717 (anhydrous ammonia) is the primary use case for the GMD-P100. Maintenance tasks — valve work, coil inspection, leak investigation — release ammonia vapor into ambient air. P100 protection covers rust particles, scale, and insulation dust disturbed during the same work. Workers in food processing cold storage facilities running ammonia refrigeration should verify that their MSA Comfo respirators are fitted and that GMD-P100 cartridges are current. See the MSA full-face respirator collection if full-face APF-50 protection is needed.

Wastewater Treatment and Biogas Operations

Anaerobic digestion, sludge handling, and aeration basin work generate ammonia off-gassing along with bioaerosols and fine particulate. The GMD-P100 covers both threat types on the Comfo platform. Workers should also consult their facility's respiratory protection program for OSHA 29 CFR 1910.134 compliance, including fit testing and cartridge change-out schedules.

Agricultural and Fertilizer Handling

Anhydrous ammonia application equipment, ammonium nitrate handling, and livestock confinement facilities all combine ammonia vapor with airborne dust. The GMD-P100 is a direct fit for tractor operators and applicators who use Comfo-platform respirators. The cartridge selection guide covers how to pair the right cartridge with agricultural exposure profiles.

Chemical Synthesis and Processing

Methylamine is a chemical intermediate in pharmaceutical, agrochemical, and solvent manufacturing. Where methylamine and ammonia co-exist with process dust or powder, the GMD-P100's dual NIOSH approvals (AM + MA) make it the correct SKU. For broader multi-gas chemical environments, evaluate the GME-P100 multi-gas cartridge as an alternative to ensure acid-gas coverage is also present.

GMD-P100 Pros and Cons

Compatible MSA Respirators

The GMD-P100 uses the MSA threaded bayonet fitting. It is compatible with all respirators in the Comfo/GM platform and explicitly incompatible with the MSA Advantage snap-on platform.

Browse the full MSA full-face respirator collection or MSA half-mask respirator collection to confirm your specific model's connection type before ordering.

GMD-P100 vs Other MSA GM-Series Combination Cartridges

GMD-P100 vs GMD (No Particulate Layer)

The MSA GMD cartridge (without P100) covers the same ammonia and methylamine vapor hazards but provides zero particulate filtration. If your operation involves only gas-phase ammonia with clean ambient air — for example, a sealed ammonia monitor calibration lab — the GMD without P100 is lighter and may have a lower change-out cost. However, virtually every real-world ammonia environment involves some level of dust, mist, or particulate: refrigeration systems generate rust and scale, agricultural settings have grain dust, wastewater sites have bioaerosols. In those cases, the GMD-P100's combined layer is worth the additional investment and eliminates the need to pair a separate particulate filter with a gas cartridge.

GMD-P100 vs GME-P100 (Multi-Gas + P100)

The MSA GME-P100 multi-gas + P100 cartridge covers organic vapor, acid gas, ammonia, methylamine, and P100 in a single body — essentially the GMD-P100's protection plus organic vapor plus acid gas. The GME-P100 is the right upgrade if your job site has a variable or unknown chemical mix, or if the hazard assessment identifies organic vapors or chlorine alongside ammonia. The GMD-P100 is the better choice when the hazard is definitively limited to ammonia/methylamine + particulate: it avoids overpaying for sorbent layers you do not need, and in some environments a leaner cartridge allows better airflow. Consult the respirator filter types guide for a detailed breakdown of sorbent combination logic.

GMD-P100 vs GMC-P100 (OV + Acid Gas + P100)

The MSA GMC-P100 OV/acid gas + P100 cartridge addresses environments where both organic solvents and acid gases are present alongside particulate — chemical manufacturing, semiconductor fab, and lab cleaning operations. It does not include ammonia/methylamine protection. The GMD-P100 and GMC-P100 serve different hazard classes: if your SDS shows ammonia as the primary chemical hazard, the GMD-P100 is the correct choice; if your hazard is chlorine + solvent + dust with no ammonia, the GMC-P100 is the right call. Running the wrong cartridge for a listed chemical hazard is a compliance failure — verify using the respirator cartridge selection guide before purchasing.

GMD-P100 Quick Answers

Is the MSA GMD-P100 compatible with the Advantage 200 LS?

No. The GMD-P100 uses a threaded bayonet connection and is designed for the Comfo platform (Comfo Classic, Comfo II, Ultra-Twin, Ultra-Elite). The MSA Advantage 200 LS uses a snap-on cartridge connection — those two systems are not interchangeable.

What is the NIOSH approval for the GMD-P100?

The GMD-P100 is NIOSH-approved for ammonia (AM), methylamine (MA), and P100 particulate service under 42 CFR Part 84. It carries MSA's NIOSH TC-approval number for the combination AM/MA/P100 cartridge designation.

How many cartridges are in a box?

Each box contains 6 cartridges. At the current list price of $227.15 per box, that works out to approximately $37.86 per cartridge.

How do I know when to change the GMD-P100 cartridge?

OSHA 29 CFR 1910.134 requires a written change-out schedule for chemical cartridges. For ammonia, change-out intervals are typically determined by a combination of breakthrough time calculations (using NIOSH or manufacturer models), maximum use concentration, and work shift duration. Unlike organic vapor cartridges, ammonia cartridges do not have a reliable end-of-service-life indicator that the wearer can detect by odor at safe concentrations — a time-based schedule is essential. Consult your industrial hygienist or the respirator cartridge selection guide for change-out scheduling methodology.

Does the P100 layer filter oil mists?

Yes. P100 is an oil-proof designation under NIOSH 42 CFR 84 — it maintains ≥99.97% filtration efficiency against both oil-based and non-oil-based aerosols, unlike N-series filters (oil-not-resistant) or R-series (oil-resistant, one shift only). This makes the GMD-P100 appropriate for environments that combine ammonia vapor with oil mist from compressors or coolants.

Can I use the GMD-P100 on an MSA Ultra-Elite full-face respirator?

Yes, provided the Ultra-Elite uses the standard bayonet connection. The GMD-P100 is compatible with all Comfo-platform full-face respirators — Ultra-Twin and Ultra-Elite — which raises the assigned protection factor to APF-50 (vs. APF-10 for a half-mask). Full-face protection is recommended when ammonia concentrations approach the upper end of the cartridge's rated range or when eye and face irritation is a concern. See the MSA full-face respirator collection for available models.

What is the difference between the GMD and GMD-P100?

The MSA GMD cartridge provides ammonia and methylamine vapor protection only — no particulate filtration. The GMD-P100 adds a P100 filter layer for simultaneous protection against fine dust, mists, and aerosols. Any environment with both chemical vapor and airborne particulate hazards should use the GMD-P100 rather than the GMD.

GMD-P100 Specifications

Helpful Buying Guides

• How to Choose a Respirator Cartridge — Complete Hazard-Matching Guide
• Respirator Filter Types Explained — N95, P100, OV, Combination Cartridges
• Organic Vapor vs. P100 — When You Need Each (and When You Need Both)
• Respirator Cartridge Color Chart — ANSI/ISEA 110 Quick Reference
• Best Respirator for Silica Dust 2026 — Buyer's Guide
• Shop All MSA Respirator Filters and Cartridges

GMD-P100 Frequently Asked Questions

Can I use the GMD-P100 with a 3M or Honeywell respirator?

No. The GMD-P100 is engineered exclusively for the MSA Comfo threaded-bayonet mount. 3M respirators use either the bayonet-style 6000-series connection or the 7000-series bayonet, and Honeywell North uses the North 7580-series thread — none of these accept MSA GM-series cartridges. For 3M filter options see the 3M respirator filters and cartridges collection; for Moldex options see the Moldex cartridges and filters collection.

How long does a GMD-P100 cartridge last before it needs to be replaced?

Cartridge service life depends on airborne concentration, work rate (breathing volume), temperature, humidity, and the shift duration. OSHA 29 CFR 1910.134 requires a documented change-out schedule — you cannot rely on smell or resistance changes alone to indicate breakthrough for ammonia. MSA and NIOSH both provide service life estimation tools; your industrial hygienist should calculate maximum use concentration and derive a time-based schedule before workers rely on these cartridges.

Does the GMD-P100 require fit testing?

Yes. OSHA 29 CFR 1910.134 mandates fit testing for all tight-fitting respirators before initial use and annually thereafter. The GMD-P100 mounts on a tight-fitting MSA Comfo half-mask or full-face respirator — fit testing is a compliance requirement regardless of the cartridge type. Quantitative or qualitative fit testing must be conducted using the specific facepiece model the worker will use on the job.

Is the GMD-P100 appropriate for refrigeration leak response?

For routine maintenance and minor leak investigations where ammonia concentrations are confirmed below IDLH (300 ppm) and the area is not oxygen-deficient, the GMD-P100 on a properly fitted, fit-tested Comfo respirator can provide appropriate protection. Emergency response, system failure scenarios, or any situation where IDLH concentrations may be exceeded requires supplied-air or SCBA — not an air-purifying cartridge respirator.

What is the difference between the GMD-P100 and the GME-P100 for agricultural applications?

In strictly ammonia-plus-dust agricultural environments (anhydrous ammonia application, livestock confinement), the GMD-P100 is the correct and more cost-effective choice. The GME-P100 multi-gas cartridge adds organic vapor and acid gas sorbent layers — useful if pesticides or fumigants are also in use on the same operation. If your SDS review confirms the hazard is limited to ammonia/MA + particulate, the GMD-P100 avoids the cost premium of the GME-P100's additional sorbent layers.

Can I buy individual GMD-P100 cartridges, or only the 6-pack?

The standard retail unit for the MSA GMD-P100 (SKU 815181) is a box of 6 cartridges at $227.15. Individual cartridge sales are not standard for MSA GM-series combination cartridges at most authorized retailers, including WC Safety. For crew-size orders or bulk procurement, the 6-pack pricing of ~$37.86 per cartridge is consistent with market rates for P100 combination cartridges.

Does the GMD-P100 protect against ammonia at all concentrations?

No. The GMD-P100 is rated for ammonia concentrations below the IDLH level of 300 ppm. At concentrations above IDLH, or where exposure duration could result in breakthrough before the next planned change-out, an air-purifying respirator is not sufficient. NIOSH and OSHA both specify that APR use requires confirmed concentrations within the cartridge's rated service range. Always use industrial hygiene monitoring data — not guesswork — to verify your exposure level before relying on this cartridge.

What respirator should I pair with the GMD-P100 for highest protection factor?

For APF-50 protection, pair the GMD-P100 with an MSA Ultra-Twin or Ultra-Elite full-face respirator. Both use the threaded bayonet connection and are in the Comfo platform. Full-face respirators also protect eyes and mucous membranes from ammonia irritation. See the MSA full-face respirator collection for current models and pricing.

Is the GMD-P100 the same as the MSA 815181?

Yes. MSA part number 815181 is the catalog SKU for the GMD-P100 Ammonia/Methylamine + P100 combination cartridge, box of 6. The GTIN is 0641817011072. The model designation GMD-P100 reflects MSA's GM-series cartridge nomenclature where "D" indicates the ammonia/methylamine chemical class and "P100" indicates the added particulate filter.

Where can I see all MSA cartridges to compare the GMD-P100 against other options?

The full MSA cartridge lineup — including standalone gas cartridges, P100 combination cartridges, and particulate-only filters — is available in the MSA respirator filters and cartridges collection. Cross-filter comparison logic is covered in the respirator filter types guide.

Does the GMD-P100 work with the MSA Low-Profile P100 filter?

No — they are different products serving different purposes. The MSA Low-Profile P100 filter is a particulate-only filter for the Comfo platform; it provides no gas or vapor protection. The GMD-P100 is a self-contained combination cartridge with both chemical sorbent and P100 particulate layers. Do not attempt to stack these; the GMD-P100 alone provides both functions.

What is the Amazon ASIN for the GMD-P100?

The Amazon ASIN for the MSA GMD-P100 (box of 6, SKU 815181) is B016N36FJC. You can purchase it directly via Amazon using the button below. WC Safety earns an affiliate commission on Amazon purchases at no added cost to you.

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