Arthur BellArthur A. Bell, Jr., P.E., is a registered professional engineer and certified mechanical, plumbing, fire, and energy conservation code official in the Commonwealth of Pennsylvania with more than 31 years of experience in the designof HVAC systems. In addition, he has been involved in the design of plumbing systems, fire protection systems, and construction field engineering-mechanical systems. Mr. Bell is also the author of HVAC Design Portfolio, published by McGraw-Hill. W. Larsen Angel, P.E., LEED AP, is a registered professional engineer in the State of Maryland with more than 25 years of experience in the design of HVAC systems. In addition, he has been involved in the design of plumbing systems and electrical systems. Mr. Angel is also the author of HVAC Design Sourcebook, published by McGraw-Hill. Read More Read Less