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Community Pdate - U Roofing Odor Concerns – FAQ’S Community pdate - U Roofing Odor Concerns – FAQ’s Q- Why did the owner choose to install an • Well-understood maintenance procedure [1] asphalt roof in the first place? Another advantage of an Asphalt BUR (built-up- roof) is its superior resistance to hail damage which Most developers & property owners look to use is particularly important in many parts of Texas. construction funds in the most efficient way possible. Notice the results of an in-depth study into how roofs This is especially true when public funds are used for performed during the 2011 hail storms that hit construction. When considering a roofing system, Dallas, TX. The study was performed by the Roofing they look at a number of factors that make up the total Industry Committee on Weather Issues, Inc. costs of a roof. These include much more than just (RICOWI). the initial installed cost. The total lifecycle cost of a roof includes maintenance costs, the anticipated life On May 24, 2011 three rounds of expectancy of the roof, the durability and the energy thunderstorms containing large hail and impacts of the roof system. tornadoes passed through portions of north Texas including the Dallas/Fort Worth After analyzing all of these factors they chose an metropolitan area. Several of the asphalt built up roof system. This decision coincides thunderstorms were supercell variety well with the guidelines that the Federal government containing very large hail. uses when determining what roof systems to use on all Department of Defense buildings. Notice these There were large areas of the two counties comments about asphalt built up roof systems from where hailstones from one to two inches in the Unified Facilities Criteria (UFC) – Roofing UFC diameter were reported. A Dallas Morning 3-110-03: News article quoted an insurance industry spokesman, Mr. Jerry Johns of the 2-8 GUIDANCE FOR ROOF Southwestern Insurance Information Service, MEMBRANES. that the damage from the hailstorms could 2-8.1 Asphalt BUR Membranes. reach several hundred million dollars. BUR systems have broad applicability for dependable low-slope roof systems with low A data form was developed to record service life cost. Consider this roof system pertinent information from each site. Data unless it can be shown that it fails to meet included location, roof construction details, important design criteria. Positive attributes generic roof material descriptions, roof pitch, of BUR membranes include: estimated maximum hailstone size at the site, • Durability with long service life and the type(s) and severity of hailstone • Low maintenance impact damage to the roofing product. Impact effects were listed on a scale of 0-5: Given all of these facts, the school district chose the roofing system with the best combination of installed 0. No apparent damage. cost, low maintenance costs, overall lifecycle cost 1. Surface impact marks without fractures and durability. or punctures. 2. Minimal damage (low severity and low quantity). Q - Are Asphalt roofs and TAR roofs the 3. Moderate amount of fractures, punctures, same things? or spalling. 4. Moderate/severe denting of metal roofing. No, asphalt built up roofs are often mistakenly 5. Severe damage resulting in potential referred to as tar roofs. Notice these comments from leakage. Wikipedia on Asphalt: A.1. BUILT-UP ROOFING (BUR) The great majority of asphalt used BUR roofs appeared to perform well. Five of commercially is obtained from petroleum. the six roofs inspected were impacted by hail Nonetheless, large amounts of asphalt occur of 2.25 inch or larger and one roof was in concentrated form in nature. Naturally impacted with 1.75 inch hail. All were rated occurring deposits of asphalt/bitumen are with damage levels 1 or 2, indicating little formed from the remains of ancient, observable damage and general good microscopic algae (diatoms) and other once- performance. Observations included scuffing living things. These remains were deposited and some gravel displacement by hail impact. in the mud on the bottom of the ocean or lake where the organisms lived. Under the heat A.2. MODIFIED BITUMEN (above 50 °C) and pressure of burial deep in A total of seven modified bitumen membrane the earth, the remains were transformed into roofs were inspected in the study. They were materials such as asphalt/bitumen, kerogen, impacted by hail from 1.75 inch to 5 inch in or petroleum. diameter with four of the seven being rated at Natural deposits of asphalt/bitumen include damage level 5 indicating they were severely lakes such as the Pitch Lake in Trinidad and damaged. One roof exposed to 2 inch hail had Tobago and Lake Bermudez in Venezuela. no damage. Natural seeps of asphalt/bitumen occur in the La Brea Tar Pits and in the Dead Sea. A.5. SINGLE-PLY SHEET MEMBRANES Asphalt/bitumen can sometimes be Three low slope single ply membrane roofs confused with "coal tar", which is a were inspected. One roof was rated to have visually similar black, thermoplastic material damage level 5 that was impacted by 1.75 produced by the destructive distillation of inch hail; this roof had multiple temporary coal. During the early and mid-20th century repairs over the reported fractures in the when town gas was produced, coal tar was a membrane so the actual damaged areas could readily available byproduct and extensively not be observed. Another roof was rated used as the binder for road aggregates. damage level 3 (moderate amount of However, since the 1970s, when natural gas fractures or punctures) when exposed to 2.5 succeeded town gas, asphalt/bitumen has inch hail. One single-ply roof did not have completely overtaken the use of coal tar in any visible damage (level 0) when exposed to these applications. Other examples of this 2 inch hail. [2] confusion include the La Brea Tar Pits and the Canadian oil sands, both of which produce odor). By encapsulating asphaltenes, this actually contain natural bitumen rather than technology stops the evaporation of lighter tar. Pitch is another term sometimes used at petroleum molecules, thus reducing fumes and odor times to refer to asphalt/bitumen, as in Pitch without impacting performance. Lake. [3] Q - So, why can I still smell it? Asphalt is considered an excellent alternative to coal Roofing Asphalt is made from the asphalt flux that tar pitch for the following reasons: remains after crude oil is refined and the lighter gases are removed. As such, it comes from a product that There are several alternatives that have is developed by nature over long periods of time. significantly lower, or no, PAH content. This means that the raw materials used to create Asphalt-based sealcoat has 1/1000th the roofing asphalt can change slightly from batch to PAH content of coal tar, and is readily batch. This natural variance in the raw materials can available at similar cost. [4] make some batches more or less smelly than others despite the use of reduced smell technology. This article in USA Today highlights the safety differences between asphalt and tar: Q - Don’t asphalt fumes cause cancer? Here are the results of over 20 years of research into "We're at a tipping point" in the movement that very question: against coal tar sealants, says Nick Kelso, owner of Minnesota-based Jet-Black The question whether asphalt fumes cause International. His seal-coating company, cancer in workers has been the subject of which has franchises in 13 states, is phasing considerable scientific investigation and debate out its use of them. He's turning to the for more than twenty years. The views of alternative: asphalt-based products that regulators and authoritative scientific groups he says are improving, cost about the same differ. For example, the International Agency and contain much lower levels of for Research on Cancer (IARC) recently worrisome chemicals. [5] announced that it has classified “occupational exposures to oxidized bitumens and their Asphalt and Tar are very different in chemical emissions during roofing” as “probably makeup and safety. Coal tar was a popular roofing carcinogenic to humans.” In contrast, the product in the past but is rarely used now. Please be American Conference of Governmental assured that there is no coal tar being used on this Industrial Hygienists (ACGIH) has concluded roofing project. that asphalt fumes are “not classifiable as a human carcinogen.” Q - What is oxidized asphalt? These differing assessments are based on Asphalt that has been treated by having air blown studies of workers, whose exposures are through it at high temperatures, making it suitable for generally much higher, and certainly of far use in roofing, hydraulics, pipe coating, membrane greater duration (years rather than hours), than envelopes, and undersealing. [6] those of building occupants. We are aware of no regulatory or authoritative scientific body Q - What is reduced smell Asphalt? that has found that asphalt roofing fumes pose Most people do find the smell of asphalt to be a cancer hazard to building occupants. [7] unpleasant. In an effort to address this, reduced smell technology was invented. Reduced Smell What are the results of studies done on those who are Asphalt does not merely hide asphalt odors, but exposed to asphalt fumes every day? An exhaustive instead encapsulates and prevents the release of low-end asphaltenes (that study was recently done into the cancer risk of those who work in asphalt plants. Here is a table that demonstrates the findings: Notice the conclusions drawn: “The big picture message is asphalt roofing products can be installed safely by roofing workers and, by extension are safe to other workers and the general public whose exposures are far lower.” [8] If I can smell asphalt fumes am I being exposed to something Notice these interesting comments from dangerous? Notice these important points from the document the LA Times: “Some Questions And Answers About Short-Term Non-Occupational Exposures To Asphalt Fumes La Brea tar pits celebrate a Created During Roofing Jobs” produced by ARMA: century of stink, ooze and Some of the compounds in roofing asphalt amazement fumes (e.g., sulfur) have very low odor thresholds (in the parts per billion range).
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