The Roan S7250 saw is designed to collect dust and can be used with or without a vacuum. When used without a vac, dust and large particles are collected in a canister. The exhaust air is filtered to prevent fine particles from coming out the other end of the saw. What little I know about this machine comes from the manufacturer’s website and a video starring Matt Risinger and my co-worker, product editor Lauren Hunter. The video (below) was shot earlier this year at the International Builder’s Show.
Roan’s saw is scheduled to be released in the first quarter of this year and will have an MSRP of around $180. It will be distributed alongside James Hardie fiber-cement siding, and is intended to help builders comply with a proposed OSHA rule, which if enacted, will reduce the permissible exposure limit (PEL) of respirable crystalline silica to 50 micrograms per cubic meter of air. The current standard is 100 micrograms per cubic meter. Fiber-cement siding is but one of many building materials that contain crystalline silica, which exists in the dust produced by cutting or grinding the material dry. People who breath a high enough concentration of silica dust over a long enough period of time can develop silicosis, lung cancer, kidney disease, and other diseases you’d rather not get.
You can reduce or eliminate the dust generated during the cutting of fiber-cement by using electric shears, a guillotine shear, or by scoring and snapping. But those methods have problems; they’re slower than cutting with circular blades and can leave rough edges. Contractors who wish to comply with the standard may be better served by a dust-collecting saw. Roan’s is not the only such saw on the market but it is one of the few that can be used without a hose. Makita has been making dust collecting circular saws since the late 1990s; their current model (5057KB) has no hose and goes for about $330. Ridgid’s R3401 has a built-in exhaust fan that blows dust out through a hose and into a drywall bucket with a special filter bag on top. Several other dust collecting saws are available but all require the use of a hose and vacuum.
The manufacturer posted a video of the saw cutting various materials and says it collects 75% of the dust. It’s impossible to verify that claim but it’s clear that the saw collects a large percentage of the dust. Whether that would be enough to comply with the proposed OSHA standard is anyone’s guess. The saw looks pretty bulky and I find it hard to believe it wouldn’t be awkward to handle. That said; it may be no worse than trailing a hose and vacuum behind you.