Inquiry (采购产品): Insulating Septic Tanks What should be the R value above a septic tank buried two feet in depth in northern MN in which the frost can be down below 4 feet? **** Hidden Message ***** Mark Wespetal 55155 USA Company: MPCA E-mail: mark.wespetal@pca.state.mn.us **** Hidden Message ***** mark.wespetal@pca.state.mn.us
