"timber cladding"

When a homeowner is considering the purchase of a steel roof a common question is whether it will increase the risk of a lightning strike. After all, steel is highly conductive, just like the materials used in lightning rods, so doesn’t it stand to reason that the steel roof will attract lightning? The short answer is, NO, steel roofing will NOT increase the risk of a lightning strike in any way. For all intents and purposes, nothing ‘attracts’ lightning. Lightning occurs on too large of a scale to be influenced by small objects on the ground, including steel roofs. The location of the thunderstorm overhead alone determines where lightning will hit the ground. A lightning bolt that is several miles long, generated by a cloud that is more than 6 to 10 miles high, is not going to be influenced by an object the size of your house. 652 Bishop St. N., Unit 2A, Cambridge, Ontario N3H 4V6 • Tel.: (519) 650-1285 • Fax: (519) 650-8081 • www.cssbi.ca The descending stepped leader of a lightning bolt doesn’t ‘decide what to strike’ until it is very close to the ground. When a cloud-to-ground lightning channel is forming, it is going to strike the ground where the opposing charges are greatest, directly underneath the storm’s most electrically active region. If you are standing at that exact location, you will be hit, even if there’s no metal within miles! Conversely, if you are farther than 500 feet from that location, you could wave your golf club or umbrella high in the air, but you won’t draw the lightning away, even slightly, from striking where it’s going to strike. Steel does conduct electricity, but steel roofs don’t attract lightning or increase the probability of a lightning strike. Four factors affect the probability of a lightning strike: • Topography: a structure located on a mountain or hill has a higher probability of a strike than one in a field. • Structure size and height: a tall structure or one that covers a great deal of ground has a higher probability of a strike than a short or small building. • Relative location in relation to taller structures: a small, short building near a taller structure has a lower probability of strike than the taller structure. • Severity and frequency of thunderstorms in the structure’s vicinity. However, on occasion, lightning does strike a house. If your home were hit, the steel roofing would disperse the energy safely through the structure. Since steel roofing isn’t combustible or flammable, it’s a low risk and desirable roofing option where severe weather is concerned -- especially for lightning. For More Information For additional information on steel roofing or other sheet steel building products, visit our website at www.cssbi.ca.

Sustainability, durability, fire resistance, structural performance and cost-effectiveness are some of the strongest reasons for using structural steel or cold-formed steel framing in mid-rise building construction. As a dependable, noncombustible material, steel-framed structures provide a wise investment for builders and the occupants who live and work in them. Steel structures provide long-term, consistent performance. • Steel framing will not rot, warp, split, crack or creep. • Steel framing is not vulnerable to termites. • Steel framing does not expand or contract with moisture content. • Steel framing is produced in strict accordance with national standards, with no regional variations. Steel is a noncombustible material and will not contribute to the spread of a fire. • Because steel is noncombustible, it reduces the fire risk to occupants, firefighters and property/business owners. Steel framing improves design efficiency, saves time, and reduces costs. • Steel framing provides a significantly greater strength-to-weight ratio than wood. • Steel framing allows for larger bays and wider frame spacing than wood construction. • Increased flexibility in bay spacing and framing layout maximizes usable floor space for owners and tenants. • Steel is typically fabricated off-site, reducing on-site labor, cycle time and construction waste. • Shorter construction time results in earlier occupancies and lower financing costs. Steel structures perform well during earthquakes and other extreme events. • Steel is a resilient material, with reserve strength and ductility that result in significant advantages in natural disasters such as hurricanes and earth- quakes, and in other extreme events like fire and blast. • Steel construction is engineered to provide a reliable, consistent load path. • Steel construction employs quality control and quality assurance procedures to ensure that the project requirements are met. Steel framing provides environmental benefits and complies with sustainable building standards. • Steel framing results in less scrap and job site waste than lumber. • Structural steel is continually recycled with a current recycling rate of 98 percent, meaning that these steels will still be in use hundreds of years from now, lessening impacts on future generations. • Steel, when recycled, loses none of its inherent properties and can be recycled into different products such as cars, bridges, cans, etc. • Steel can be used to comply with the requirements of sustainable design standards such as the International Green Construction Code (IgCC), ASHRAE Standard 189.1 (Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings), and the National Green Building Standard (ICC-700). Steel can also provide credit points for green building rating systems like the USGBC’s LEED (Leadership in Energy and Environmental Design) and the Green Building Initiative’s ANSI/GBI-01 (Green Building Assessment Protocol for Commercial Buildings).  

Executive Summary The aim of this fact sheet is to advocate an alternative solution for the Steel Industry in regards to restrictive code provisions for explosion venting that are now mandated by the Ontario Fire Code (OFC). Due to a September 2000 amendment of code provisions dealing with explosion venting in the OFC, explosion vent designs were required to be in conformance with NFPA 68, the National Fire Protection Association’s (NFPA) Guide for Venting of Deflagrations. NFPA 68 gives a prescriptive solution that has upper bound limits on size and mass of an explosion vent panel, which the Steel Industry finds are too small to be practical. The Canadian Steel Construction Council (CSCC) investigated this problem and identified an alternate design guideline from the Factory Mutual Insurance Company’s (FM) Property Loss Prevention Data Sheets, numbered 1-44 and entitled “Damage Limiting Construction”. FM’s 1-44 Data Sheets can be used to develop an alternate solution for explosion venting that exceed the size and mass limits of the NFPA 68 prescriptive solution, and can be submitted for approval under the Compliance Equivalency provisions in the OFC. With the introduction of an objective based National Building Code Canada (NBCC) in 2005 followed by Provincial code adoptions in 2006 it would be worthwhile to establish a precedent through the Compliance Equivalency provision in the OFC. Once a precedent setting case occurs, the “acceptable solution” or “compliance alternative” would go on record and aid in resolving subsequent proposals for Compliance Equivalency, and also support a future technical change in the OFC. The CSCC by way of this fact sheet would advocate this alternative solution for the Steel Industry when designing explosion vent panels in steel framed buildings.

One of the most common questions asked by homeowners about the installation of their steel roof is whether an underlayment is needed. The answer to this question is “yes” in most situations. The underlayment plays a critical role in controlling the migration of condensation that might develop on the underside of the steel sheet thereby preventing accumulated water entering the building resulting in costly damage.

It’s a fact that buildings consume two thirds of all the electricity produced in North America and one third of all the energy produced in North America. While it is recognized that cooling and heating costs can be reduced by adding insulation under the roof surface, there is a diminishing return on the strategy of increasing insulation to conserve energy costs. This is where “cool roofing” can play a role in further reducing the energy consumed, and in minimizing the Heat Island effect created in the big urban cities. Cool roofing relies on the properties of reflectivity and emissivity of the roofing material. Reflectivity Reflectivity is the ability of the roof to reflect solar radiation back into the atmosphere. Its primary measure is solar reflectance - the proportion of the total solar radiation that is reflected back to the atmosphere. Any solar radiation that is not reflected is absorbed into the building envelope, requiring further energy to cool the building; or partially convected into the atmosphere increasing the ambient air temperature in the surrounding environment (Heat Island effect). The measure of reflectivity is the Solar Reflectance Index (SRI) which takes into account the properties of the material as well as the cooling effect of wind passing over the roof. The SRI for a low slope roof will be 0 for standard black (reflectance 0.05, emittance 0.90) and 100 for standard white (reflectance 0.80, emittance 0.90).

Steel is a major and essential construction material, offering unique value and unmatched performance in many end uses. Steel is strong, safe, durable, versatile, resilient and cost-effective. Steel is sustainable, with the exceptional environmental advantages of being highly recycled and infinitely recyclable. Steel is tough and does not rot, spall, split or absorb moisture and is resistant to pests, unlike other building materials. And from an aesthetic or architectural viewpoint, steel structures can easily deliver creative design options and offer excellent value. Steel is the fabric of life.