FAQ - Initial Equipment Specification
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FAQ - Initial Equipment Specifications
G90 Galvanized Steel
Titan Air standard equipment is constructed of G90 galvanized steel. This provides a durable finish that resists rust and corrosion. Compared to enamel paint and enamel paint with heresite finishes, the G90 construction offers the best scratch and abrasion resistance. It is also the most economical solution compared to the other finishes.
Titan Air has an in-house painting department that allows us to offer painted finishes in any color. This paint finish provides enhanced rust and corrosion resistance compared to G90 galvanized sheet metal. This enamel paint also includes UV inhibitors. Multiple/custom colors are available.
Heresite or Epoxy with Painted Enamel
For enhanced protection, Titan Air offers equipment that can have the exterior casing, interior liner, blower, control vestibule, and door coated with heresite. The exterior is then painted with enamel for added protection and to add UV resistance. The heresite coating is used to prevent corrosion that occurs due to air particulates in settings such as wastewater treatment plants and natatoriums.
Stainless steel sheet metal construction is also offered by Titan Air. This may be required for equipment being installed at food manufacturing or wastewater treatment plants. Units can also be constructed with only the interior liner being constructed of stainless steel, this can be beneficial in settings where the equipment will be “wiped down” periodically.
Titan Air equipment is regularly installed in areas of high elevation. It is important to ensure that Titan Air is informed during the quoting stage of a project if the unit is at an elevation over 2000 ft above sea level (2000 ft for indirect – 3000 for direct fired).
The higher the altitude, the less dense the air becomes, resulting in air that has less heat-carrying capacity. An HVAC unit’s CFM (cubic feet per minute of air) and temperature rise requirements are used to calculate the required BTU. Compared to a unit installed at sea level, a unit at a higher elevation will require less BTUs to meet the CFM temperature rise requirements.
Failure to disclose the elevation that the HVAC unit will be installed at during the start of the project can result in the unit being sized incorrectly. If a specific CFM and temperature rise are specified, and Titan Air is not informed that the project is at a high altitude, it can result in larger, more expensive burners/heat exchangers/heating coils being sourced than would actually required at the installed altitude.
External Static Pressure (ESP) is the measure of all resistance in the airstream that the fan in an HVAC system has to work against. This includes all items not supplied by Titan Air. Total Static Pressure (TSP) includes the ESP plus the resistance of the equipment and accessories provided by Titan Air (HVAC unit, filters, dampers, diffusers, hoods, coils, etc). This is measured in inches of water column.
Static pressure has a large impact on the design of the equipment being quoted by Titan Air. Often the external static pressure is just “guessed” or loosely estimated during the quoting stage of the equipment. One rationale is to “pad” or overestimate the ESP so that the unit will be able to handle whatever the conditions are at the jobsite. However, it is important to take time to properly determine ESP as it relates to several design and installation considerations:
- Motor Horsepower – The horsepower of the motor(s) chosen is based on a combination of the required cubic feet per minute of air (CFM) and the TSP. Overestimating ESP can result in a larger than necessary motor, while underestimating ESP could result in a smaller motor than required, in both cases efficiency will be lowered…and in worst cases a replacement motor may need to be installed. Using a larger than needed motor will also increase the overall unit cost.
- Installation and Setup – Titan Air motors up to 30 HP come with adjustable motor sheaves that allow for jobsite adjustment of motor RPMs due to differences between the previously estimated ESP and what actually exists. However, adjusting these at the jobsite will result in additional expenses due to labor costs, and if an extremely large adjustment is required, additional sheaves may need to be sourced.
In general applications a forward curved fan is the most economical solution, they generally operate at lower speeds and are designed to handle high flow rates at lower pressures. Forward curved fans are not as efficient as the backwards inclined or airfoil fans, but this is not always crucial because most applications are generally lower horsepower.
Airfoil and backward inclined fans are more efficient than forward curved, with a performance characteristic curve that is stable over a wide range. They also have a non-overloading fan horsepower curve, essentially this means that horsepower will increase to a maximum as the airflow increases, eventually dropping back off again towards free delivery. By selecting a motor to accommodate the peak horsepower, there will be no risk of motor overload or burnout due to variations in the system resistance or airflow as long as the fan speed remains constant. Forward curved fans do not share this characteristic.
This is beneficial because if the airflow design criteria changes or external static pressure was not estimated correctly, there will not be a situation where the motor will become overloaded. Backward inclined and airfoil fans remain more efficient than forward curved when the filters in a unit become dirty/clogged. Airfoil and backward inclined fans are generally used in units with higher total static pressure as well as in specific environments that may also benefit.
While backward inclined and airfoil fans are initially more expensive than forward curved fans, their higher efficiency can in some cases result in this cost being paid back as they can require up to 15% less power than a forward curved fan doing the same duty. One last consideration to choosing a backward incline or airfoil fan is that they are primarily suited for clean air applications, and while they can handle particles like dust that are not sticky, they are not recommended for conditions where other particle types are present in the air.
Regardless of the fan type that is selected it is very important that the correct fan size is chosen in order to best meet the criteria of the application. Proper fan size selection will also minimize the noise levels of the fan while in operation.