Are you Engineering or Guessing?

Are you Engineering or Guessing?

engineersToday’s engineers are excellent at designing mechanical systems for different types of buildings and applications. These include academic, commercial, medical, pharmaceutical, institutional, and many more. They create systems that are energy efficient, can control indoor climates within tenths of a degree, and maintain pressurization levels between areas to ensure people’s and product’s safety. Not all buildings are new, however, and redesigning systems in existing buildings is a completely different endeavor. In such re-designs and retrofits, the role of testing, adjusting, and balancing (TBA) companies can be critical to the successful outcome of the project.

Buildings are re-designed and retro-fitted for various reasons. These motives include HVAC equipment upgrades for increases in energy efficiency, or to replace older equipment prior to failure. The re-design can include changes to air handling units, fans, pumps, and other system components. Mechanical redesign also occurs when building usage is altered, or new tenants move in. Let’s look at the vital role that TAB companies play in this re-engineering process.

Mechanical Upgrade Projects

As mechanical equipment ages, it is replaced for various reasons, sorne of which are outlined above. The mechanical designer’s role is to select the right equipment for the present system/building requirements. What process do they use for this? Do they review shop drawings from when the equipment was originally purchased? This could have been 5-10-15-20 years prior. Do they examine the most recent balancing report? This document can be obsolete by that time. Basing the selection on old, dated, potentially invalid information is an extremely dangerous practice.

What changes were implemented over the years? Was the equipment operating at its design leve!? Was that operating level enough to satisfy the current system requirements?

This is where the TAB agency is critica! to the designer. The present equipment performance must be tested to determine the present operational leve! prior to the designer selecting the new equipment. Reviewing the installation can provide the designer with updates on system changes and modifications that have been implemented. This hard data can then be used along with any observational data, and new design calculations can be made to ensure the new equipment is properly selected.

Tenant Upgrade And Modified Application Projects

Mechanical system modifications to suit new tenants, or new applications, are another area in which TAB companies are important to designers. Testing current system capabilities provides the designer with the knowledge to base the redesign on factual data. How much airflow is available, from the existing system, for the modified area? Without empirical system data, a designer is simply guessing. In some situations the design for a new tenant occupying half of a floor of a multiple-storey building, was based on an expected airflow level that was greater than the airflow being supplied to the entire floor. How will that ever work? IT WON’T.

The Risks Of Guessing

Scenario One- A possible scenario when guessing on new equipment selection for an existing system

The new equipment is installed, the system changes have been implemented, and now the testing and balancing technician is on site. The new air handling unit is performing according to the selected operating level (Based on the original design numbers), but the system does not have sufficient airflow and static pressure to satisfy the entire system requirements. Additional ductwork was added over the years, providing airflow to adjacent, now conditioned space, and now the airflow is insufficient to meet the new requirements. If the designer selected the equipment with allowances for additional capacity, then this is a small problem. A pulley change should do the trick to increase the fan to capacity. Oh-the building is scheduled to be put into use tomorrow, so now it’s a scramble to try and get a pulley change done in time, and get the system balanced and completed on schedule. Let’s not forgot about the cost factor-now someone has to order, pick-up, and install the pulley. Then the system has to be re-tested, and finally can be balanced. This is an additional cost, and a last-minute scramble, all due to the lack of a pre-test. After paying for that, has any money been saved by not pre-testing? A good balancing company doing a proper pre-test can save many headaches, help ensure project completion goes smoothly, and prevent last minute cost surprises.

Scenario Two-A possible scenario when guessing on existing equipment performance for a new system

This second scenario can occur when a new system is designed and connected to existing equipment. If the equipment’s performance is lower or higher than assumed, again there will be scrambling at the end of the project to make the system work. What if the fan or pump cannot supply enough air or water to meet the system requirements? What if a pulley change cannot be made because the motor is loaded, or the fan is already operating at a critical (maximum) speed? Or if the pump is operating at its maximum, and an impeller change cannot be implemented? This type of situation can happen too many times. Now it’s the last minute, and there’s a real problem making the system work. This whole situation can be prevented with proper system pre-testing. Pre-testing would uncover the equipment shortfalls during the design stage, and the designer would have an opportunity to make equipment or system changes that would ensure the final design is one that meets the needs of the building.

Pre-testing your way to a great project completion

To achieve a successful project outcome, it all starts with good design work by the consultants. Accurate design needs to be based on proper assessment of reliable data. This data is determined through pre-testing of systems. Good designers don’t guess, they engineer systems based on accurate information. A good balancing company is a vital cog in the process of good designs, and great systems. When the project goes smoothly, and the design intent is achieved, it’s a tribute to the designer. Using testing and balancing professionals to pretest during the design stage assists the designer, and is a critical first step towards a project that ends with safe, comfortable buildings. That is the objective on every project!