Commercial HVAC system Inspection

Commercial Rooftop Unit (RTU) Basics

The RTU is the most widely used commercial heating and the cooling unit found in the U.S. The rooftop unit is sometimes called a package unit, as all its components are contained in one unit. The RTU is usually a direct-expansion (DX) unitary system, which means that the air is cooled by a refrigerant, and…

Central Plant Systems and Chilled Water Systems

Central plant systems typically consist of components to provide chilled water for cooling, and use a boiler for heating water. Boilers typically operate at 17º F to 200º F, although most units that are manufactured currently are computer-controlled and may operate at as low as 100º F, depending on the exterior temperatures and the heat…

Reference Sheets for Low-Slope Roof Inspections

CCPIA has downloadable Reference Sheets for Low-Slope Roof Inspections for members to use. The types of low-slope roofing systems included are built-up roofs (BUR), modified bitumen roofs, single-ply roofs (TPO, PVC, EPDM), and metal roofs. Each reference sheet includes: a description of the roofing system and relevant subcategories; its principle components; average lifespan; its pros;…

Pre-Inspection Process for Commercial Roofing Systems

Scope of the Inspection Standards of Practice When entering into an agreement to inspect a property, it’s common for the inspector to include in the agreement the Standards of Practice that will form the basis for his inspection. Members of CCPIA perform commercial building inspections according to the International Standards of Practice for Inspecting Commercial…

The Thermodynamics of Thermal Insulation

Terms You Should Know Thermal conductivity Thermal conductivity is the K-value. It is the measure of a material’s ability to conduct heat. A low K-value indicates that the material does not allow heat energy to easily pass through. According to the National Roofing Contractors Association (NRCA), a material must have a K-value of 0.5 or…

Types of Low-Slope Roof Thermal Insulation

The insulation used in low-slope roof assemblies typically falls into one of the four categories: rigid board insulation; dual-purpose structural deck and insulating planks; lightweight insulating concrete (LWIC); or sprayed polyurethane foam (SPF). Rigid Board Insulation Rigid board insulation is the most common type of insulation used in low-slope commercial roofing. It is made from…

Area of active ponding on the roof

Why Low-Slope Roofs Fail

All buildings are capable of having an unlimited physical service life, but not an unlimited economic life. No other building system surpasses roofs as a source of litigation. Roofs may fail for either economic or technical reasons. Economic Reasons for Roof Failure When decisions are made on how to spend money on the construction of…

Low-Slope Roof Construction and Failure Assignment of Responsibilities

The complexities involved in adequately designing a roof for optimal long-term performance are reflected by the number of factors that a designer must consider, including: original construction and life-cycle (long-term) costs; energy conservation scheme; value of building’s interior contents; required long-term service life; basic roof components (deck, insulation, membrane, accessories); availability of qualified contractors/workers; environmental…

Low-Slope Roof Components

The following information is a general overview of basic and accessory low-slope roof components, their major design factors, functions, and common failures. The three main components of a low-slope roof are the structural deck, the thermal insulation, and the membrane. Other vital parts of a low-slope roof include the flashing and air retarders, although these…