Replace HVAC Systems

The National Park Service (NPS) issued a task order to HECO Engineers (HECO) to complete the Scoping Trip Report that documented the condition of the Alan Bible Visitor Center (ABVC) heating, ventilation, and air conditioning (HVAC) system located within the Lake Mead National Recreation Area. Stantec provide the HVAC subconsultant support.

The ABVC, located near Boulder City, Nevada, was constructed in 1966, as part of the NPS Mission 66 program during the agency’s 50th anniversary. The ABVC has since gone through various upgrades to bring the building up to code, improving accessibility and overall energy efficiency. The building consists of information desks, an exhibit hall, auditorium, gift shop, offices, and public restrooms. The HVAC units consisted of four roof-top units (two 12-ton units, one 15-ton unit, and one 4-ton unit), three 1.5-ton split system units, exhaust fans, and ductwork.

Based on the age, condition, maintenance cost, and energy efficiency, HECO recommended three of the rooftop units (the fourth unit was installed in 2018) and all split system units be replaced with Energy Star rated units for improved energy efficiency decreased maintenance costs, and increased reliability. One of the rooftop units was recommended to be replaced with a multizone variable volume unit with zone terminal units to allow better zone control. The ductwork that was installed in 2010 was recommended for reuse as much as possible. Interior ductwork and insulation serving one of the rooftop units should be replaced, with the layout optimized to reduce fan sizing and increase energy efficiency. In the auditorium, it was recommended the supply registers be replaced with a high throw type diffuser. The public restroom exhaust fan is recommended to be replaced with an electronically commutated (EC) motor fan for increased energy efficiency. An air transfer boot is recommended to be added over the restroom doors.

Electrically, HECO documented a clearance deficiency between the AC unit Control/Power panel and structural metal parts of the roof structure. The available working clearance at this location varies between 4” to 18”. This is a safety issue posing an electrical shock hazard to maintenance personnel. HECO recommended relocating the Control/Power panel remotely from the AC unit to a location on the roof where proper safe working clearance of minimum 42” can be obtained.

Services Provided by HECO Engineers:

• Condition Assessment
• Design Services
• Electrical Engineering
• Scoping Report