Albedo is the measure of how much solar radiation is reflected by a surface. It’s expressed as a fraction or percentage between 0 and 1, where high albedo means the surface reflects most of the sunlight (like fresh snow), and low albedo means it absorbs more energy (like dark asphalt). This concept is key in understanding how surfaces influence the Earth’s energy balance and climate. Absorption, on the other hand, is about how much energy the surface takes in, which is essentially the complement of reflectance. Scattering describes light being redirected in many directions and can affect brightness, but it’s not the overall reflectivity measure. The term infrared index isn’t a standard measure of reflectivity either. So, the quantity that directly quantifies the fraction of incoming solar radiation that is reflected is albedo.

In Alberta, the enforcement of boiler regulations is handled by ABSA, the Alberta Boilers Safety Association. ABSA administers the province’s boiler and pressure vessel safety program, issuing permits, conducting inspections, and licensing boiler operators and installations to ensure safe operation. Their authority comes from provincial laws like the Safety Codes Act and the Alberta Boiler Safety Regulations. While organizations such as ASME provide design and construction codes and CSA sets national standards, they are not the enforcing body in Alberta, and OSHA is a U.S. agency not applicable to Alberta.

Testing medical gas piping relies on a hydrostatic test that pushes the system beyond its normal operating pressure to reveal leaks or weak joints. The minimum test pressure is set at 1.5 times the maximum operating pressure of the system. For many medical gas installations, that results in 150 psi as the minimum test pressure. This provides a safe margin—high enough to uncover defects, but not so high as to risk damage to the piping or components. A test pressure of 100 psi wouldn’t give sufficient margin, while 200 or 250 psi would go beyond the standard minimum.

In piping, some fittings earn nicknames based on their shape. A “lobster back” refers to a double back elbow, a fitting that makes a return turn by two successive bends in a compact space. It's basically two elbows combined to create a tight 180-degree turn, which is why it’s classified with elbows rather than with tees or reducers. A standard elbow is a single bend, a tee adds a branch, and a reducer changes the pipe size. So the lobster back is the double back elbow.