Energy savings analysis has been around for years. There are any number of Internet-based calculators, formulas and procedures for estimating the savings associated with products or actions undertaken to reduce or avoid energy usage. Energy savings is but one component of a much more comprehensive analytical process referred to as life cycle analysis or LCA. But LCA is not nearly so well-defined. Unlike energy savings analysis, which considers a limited number of variables that can be reasonably well defined and quantified, there is no uniform procedure for LCA.
There are some Internet-based calculators for LCA, but they range from being over-simplified to exceedingly complex; from being biased toward individual products or special interests to being overly generic and meaningless. Some approaches to LCA only consider short term direct financial burdens while others consider more indirect or subjective costs both upstream and downstream in the life of a product.
A mainly financial LCA approach for comparing roof systems might consider the following:
- Installation – product cost, installation costs, tear-off costs, disposal costs, business disruption costs.
- Long Term Durability – routine maintenance costs, roof replacement costs.
- Repairs – roof repair costs, interior damage repair costs.
- Energy Savings – estimated savings, rebates and incentives.
- Warranty – cost premiums.
On the other hand, a highly comprehensive environmental-based approach might entail the evaluation of all material and energy inputs and outputs at every stage, from the creation of natural resources through extraction, manufacture, use, and demolition, and disposal of a product. Consider the complexity of the following extreme LCA flow example:
BANG ? Earth Appears ? Life Begins ? Dinosaurs/Other Creatures Appear ? Creatures Die/Turn Into Fossil Fuels ? Human Race Appears/Evolves ? Resources Extracted (fossil fuels, salt, etc.) ? Resources Transported to be Processed/Refined ? Process/Refine Raw Materials ? Process Components (film, scrim) ? Produce Product Components (membrane, rigid parts, etc.) ? Transport for Fabrication ? Fabricate and Assemble The Duro-Last® Cool Zone® Roofing System ? Deliver to Jobsite ? Installation ? Roof In Action (energy savings/heat island mitigation/global warming or cooling or both) ? End of Useful Life ? Removal/Disposal ? Recycle and/or Transport to Landfill ? 100,000 to 1 Million Years of Decay and Revert to Fossil Fuels, Salt, etc. ? Another BANG!? Or Re-Extraction?
Although this second example seems extreme or absurd, it makes the point that there can be limitless considerations in a comprehensive LCA. The difficulty comes in deciding how far to go and making fair and objective assumptions of all criteria at each stage in the life of the product or system. One of the best things LCA helps accomplish is identification of opportunities for improvement. The important thing to remember in addressing this continuous improvement process is to remember that every action has a reaction, so don’t rob Peter to pay Pa
Occasionally, we come across articles that we feel will be beneficial to our readers. John D’Annunzio has written a series of articles for FacilitiesNet discussing factors that determine roof longevity. Below is a brief description and link to each article.
Part 1: Proper Design Improves Roof Longevity
This first article discusses key components to proper design that include wind uplift calculations, drainage design, thermal factors, perimeter edge design, and existing building conditions. It also discusses the selection of materials and systems that are compatible with existing building conditions. Proper design should always focus on providing a long-term roofing system.
Part 2: Focus On Roofing Materials And Workmanship To Improve Longevity
The second installment explains that not all roof materials are the same and not all materials are suitable for all buildings. Applied materials should be new, free of all excess moisture, and manufactured in compliance with ASTM standards. Proper material storage at the project site is also required.
In addition, the roof is one of the only major building components that is partially or fully constructed on-site. A large percentage of premature roof failures occur due to improper workmanship.
Part 3: How Weather And Maintenance Impact Roof Longevity
Finally, the third article describes how applications of roofing materials in conditions not suitable to the material’s constraints (too hot, too cold, in wet weather) will contribute to premature failure.
No matter the roof type, all roofs require a certain level of attention. Roofs are exposed to the elements 24 hours a day, every day of the year. One of the most important reasons to implement an annual roof maintenance program is to extend the service life of the existing roof system.
In our introductory post about this topic we discussed how fall hazard control – and corresponding cost control – is increasingly being considered in constructability analyses. “Constructability” is a project management technique that reviews a building project from start to finish, during the pre-construction phase.
We also introduced the three types of fall hazard control: elimination, prevention, and protection. In the previous post we discussed elimination. We will discuss protection in a subsequent post.
Constructability techniques that address fall prevention need to be identified in the planning or design phase of a project’s life cycle but can also be implemented at later stages. The reliance on equipment and physical installations as opposed to work process planning allows fall prevention consideration to take place throughout a facility’s life cycle.
Here are some examples of fall prevention techniques that have gained wide acceptance:
- Extensive use by all the trades of mobile elevating work platforms and telescopic scaffolding
- Crane-suspended baskets and suspended scaffolding are now recognized as being inherently safer than reliance on personal fall protection equipment
- Bringing the work to the worker who is located in a guarded work location surrounded by railing has many productivity and safety advantages
- The use of warning lines for low-sloped roofing personnel is a significant life saver, if measures have been taken to equip the six-foot area adjacent to the fall hazard with a more substantial method of protection
- The use of perimeter netting around the edges is becoming more common especially on foreign projects
- Barricades of all kinds provide protection by preventing exposure to edges or openings and can remain behind to be used for future applications
- Self-adjusting lanyards (basically horizontal lifelines) are especially flexible in their ability to limit access to perimeter hazards.
The passive nature of fall prevention systems is dependent on adequate inspection and maintenance to preserve their effectiveness, as is an understanding of the fine line between prevention and protection.
The next post in this series will discuss recent regulatory changes that recognize prevention systems and the differences in their anchorage requirements.