What type of respirator do you use for cutting hardiplank?

You should use a full face or half mask respirator (not the cheap disposable dust mask). Stick with a known brand name such as MSA, North or 3M. Most of these masks are made in a couple of different compounds; 1. rubber-cheaper masks, isn't as flexible, less comfortable to wear or 2. Silicone-more expensive, fits a lot of faces, very flexible and conforming.

Masks should be fit to ensure that they fit your face properly. If you buy your mask from a retailer such as Home Depot; they WILL NOT be able to conduct a fit test to ensure proper fit. Most people fit a medium mask (80 % of the population) but there are exceptions (smaller people, asians, women etc) that require smaller masks. The user must be clean shaven where the seal of the mask fits with the face (in order to be compliant with NiOSH National Institute for Occupational Safety and Health-which all respiratory protection is certified by). failure to be clean shaven could result in the dust passing by the skirt of the mask and entering your lungs, which over time could cause Silicosis.

The filter that is required for the mask is a P100, which will stop particles down to 0.03 microns in size. The cartridge colour is standard between all major manufacturers and in this case the cartridge is purple. You must use the same manufacturers mask and cartridge; do not mix!