3M 4251 Half Face Masks

3M 4251 half masks are among the most popular '28 day' respirators.

The manufacturers description is as follows:

• 3M 4251 Organic Vapour and Particulate Respirator: FFA1P2R D Gases/Vapours :10xWEL* or 1000ppm whichever is lower; Particulates:10xWEL* 

The A1 gas filters will protect against organic vapours (boiling point >65 degrees C) and the P2 filter will protect against airborne particulates. This combination of filters makes this mask popular with paint sprayers.

Lets go through some of the 3M bullet points for the 4251 mask.

• Maintenance free design for maximum safety and simplicity.

The 3M 4251 mask is ready to wear once removed from its foil bag.

• No maintenance records are required if disposed of within one month.

If using a half mask with replaceable filters records need to be kept of filter changes. The 3M 4251 mask does away with these requirements.

• Replace after 28 days or when damaged, breathing resistance increases or breakthrough occurs, whichever occurs first.

The whole 4251 mask is disposed of after 28 days OR sooner if the gas filters become saturated or the particle filters clogged.

• 2 large bonded carbon filters for low breathing resistance.

The filters on the 3M 4251 mask are integral and cannot be changed.

• Low profile design for better peripheral vision.

Because the filters are built in to the mask they intrude less on the field of vision.

• Low resistance parabolic valve to reduce heat build-up.

The 3M 4251 mask has an exhalation valve (all half face masks do!).

Downloads: 3M 4000 Series datasheet.

3M 4000 series half face mask fitting video.


Where to buy 3M 4251 respirators: DustMasksDirect.