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Environmental Specifications: Performance Based vs. Prescriptive Based

Constructability is key to successful specification writing.

November 1, 2017

New projects and construction like roads, bridges, and buildings often face an incredible amount of "red tape" in order to succeed. The "red tape" can take the form of contract negotiations, submittals, inspections, rejections, specifications and egos. Each key stakeholder has an opinion to hear, supervisor to satisfy and checklist to complete, making it easy to overlook the absolute goal which is the successful, effective and profitable completion of a project. 

Frequently, excessive adherence to these formalities delays project completion times with the project becoming less cost effective with each passing day. Prior to breaking ground, stakeholders rush to cross items from a checklist to establish a meaningful state of progress with less attention paid to the efficacy of the binding specifications. Many projects lean heavily on following prescriptive specifications in a concerted effort to accommodate all necessary requirements, appease all stakeholders, and establish a fundamental plan for their construction. 

When dealing with private stakeholders, landowners, or government municipalities these requirements and related bureaucracy can be even more burdensome and, at times, not related to the overall wellbeing of the project. Often, the experts in a particular area - those who do the work and warrant the results - are overlooked because their recommendations may deviate from the historically accepted prescriptive model. In such instances, re - examining contractual obligations and the goal of the work is necessary to establish the most beneficial outcome for all parties. The reliance on past successes and ability to prove a knowledgeable history in such dealings while demonstrating a progression towards a beneficial outcome cannot be ignored.

The line between performance based and prescriptive based specifications is a tight rope for contractors, agencies, and financial lenders who are backing any such project as it unfolds. For each to feel established, vested, and important in the process - all must be listened to and the necessary steps taken to ensure the measures of each individual entity are being rightfully considered.  However, we cannot forget that the success, profitability and efficacy of the project itself supersede personal feelings or agenda.  

Prescriptive Based Specs

According to the National Ready Mixed Concrete Association, “a prescriptive specification is one that includes clauses for means and methods of construction and composition rather than defining performance requirements. Many times intended performance requirements are not clearly indicated in project specifications and the prescriptive requirements may conflict with the intended performance.”  More directly, the project was 'engineered to the point it couldn't be constructed'. 

One of the more controversial aspects of prescriptive based specifications with regard to construction is the implication of a design. A prescriptive specification could contradict the intended goal or purpose from the standpoint of the manufacturer, municipality, or governing body overseeing any such project. As such, many contractors and companies will focus on the necessary and intended purposes, especially when considering the environmental impacts, as opposed to following a design plan without room for any allowable modifications. Amplified focus on prescriptive methods prevents every stakeholder from innovating and applying current techniques.  Prescriptive specifications work best as a foundation and deliver the worst when treated as an unbreakable commandment.

Consider how changes are correlated in the opposing form of performance based specifications.

Performance Based Specs

Any deviation from prescriptive construction performance initiatives will often be denied. Change is hard. While the benefits of proposed modifications may be apparent to an expert in the field, far too many projects are commonly managed where the regulating body of a construction project is more concerned with monetary limitations or audits than what is often a simple and, many times, cost effective change.

One of the most common areas in which this occurs is revegetative seeding and reclamation. While strict guidelines exist in contracts for construction personnel, the requirements will sometimes not promote sustained vegetation growth in the long-term and may not provide the necessary focus to ensure a quality finished product. Many factors need to be considered when addressing the revegetation concerns. Normally, at least two growing seasons must occur in order to regain proper and necessary growth. The current habitat, soil fertility, slope and seeding methods must all be considered when establishing a long-term plan for proper erosion control while minimizing the environmental impacts of a construction site.  

In such instances, it is best to partner with a professional group which exhibits a strong history of reclamation and revegetation successes to elevate the modifications or design needed for not only the environment but a more complete and well-rounded product. Instead of forcing a method because it is comfortable or 'the standard', ensure your project receives the best possible care with optimum results for future sustainability and success.  Performance specifications focus on sustainability and success.

E2RC is committed to meaningful construction performance, following established protocol and providing professional opinions where needed. Our experts can address any natural impacts regarding specific construction measures with an ability to minimize the impact on the environment and protect the necessary functionality around each and every construction project site. E2RC is committed to the following four principles to confirm each effort confidently meets the registered goal.
  1. We are a partnership focused with very profitable results for every member as the measure of the relationship.
  2. We follow the golden rule.
  3. We THINK and ACT with intention and purpose.
  4. We believe in candor and honesty.

Since 2006, E2RC has been leading the focus on stormwater compliance and site management with activities expanded more recently to include erosion control and modifications on specialized construction techniques. Any and all of your questions regarding what impact new or additional construction may have on the surrounding environment can be readily addressed by one or a team of our willing and ready professionals. Contact us at 505-867-4040 or
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