When pressurizing insulation in the dense pack method the insulation acts as a liquid moving into inaccessible areas. Different types of insulation works better for this application. Dense packing walls helps stop air movement in wall cavities. This can help in case of a fire. Fire will be fueled by the moving air and move the fire into other areas of the house at a faster rate.
Before starting dense packing walls it is all ways important to make a list of tools you will need for the job and train the installer how to remove then replace siding (vinyl, aluminum, steel and wood). There are many blowing machines that can be used for this application some machines are designed for dense pack. The hose will need to be reduced to fit a 1 ¼ or 1 ½ inch clear hose (these hoses are made for winter and summer conditions). Next the installer should check to make sure the insulation is being installed at the manufactures specs. (This can be done by using a density box or pressure gauge).
Once the siding is removed drill one 2 ½ inch hole half way up in every empty cavity. It is all ways a good idea to measure how far down and up you will feed the hose then mark the clear hose with a piece of tape. Then feed the hose to the bottom of the cavity keeping the hose up about 5 inches from the bottom.
After you start blowing the insulation it will start to fill up and pack. When it packs it will stop the blowers. Pull the hose out slowly to ensure the cavity gets packed completely. When the bottom is packed feed the hose to the top and repeat the same method.
Finish by installing a wood, plastic or foam plug.