Contractormag 2806 Creedemountains

School in Creede, Colo., aiming for LEED Gold

Jan. 11, 2016
Creede, Colo., has a colorful history. Bob Ford, the man who shot outlaw Jesse James in 1882, was killed in a gunfight in Creede.  The 530-mile roundtrip to Creede was one of several unique challenges they’d encounter over the course of the project. At the new school, heavy insulation joins high-efficiency equipment and local building materials on the drive to gain LEED credits.  
Creede is a 265-mile drive from the Rogers

CITY OF CREEDE, COLO. — The silver belt buckle reads “Sheriff” as it glistens in the afternoon sun. Lawman Fred Hosselkus stands outside the courthouse, looking down Main Street from under the brim of his five-gallon hat. 

It’s tourist season in Creede, the only time of the year that the one-horse town hustles. Today, it’s the only town in Mineral County, nestled in a crescent-shaped bowl at 9,000- ft. above sea level between two mountain ranges.

Bob Ford, the man who shot outlaw Jesse James in 1882, was killed in a gunfight in Creede. Despite its colorful history, Creede’s current residents maintain a relatively normal existence in one of Colorado’s most beautiful and remote areas. 

As of this year, they even have a new K-12 school, complete with modern, high-efficiency HVAC systems and an architectural style that fittingly blends wood, metal and stone.

Shootin’ for Gold

At the new school, heavy insulation joins high-efficiency equipment and local building materials on the drive to gain LEED credits.

General contractor, Neenan Archistruction, broke ground on the 37,000-sq.ft. school in May of 2014. In July, Rogers and Sons, Inc., arrived on the job in force. The design/build HVAC firm out of Denver handled all facets of the heating system in-house, from sheet metal to controls. 

The 530-mile roundtrip to Creede was one of several unique challenges they’d encounter over the course of the project.

“It’s not our first long distance rodeo,” said Aaron Ellis, head of field operations for Rogers. “We cover the whole state, so working out of hotels and trailers isn’t rare.” 

With LEED Gold certification being sought, energy efficiency and low lifecycle costs were major criteria. Weather can be fickle in Creede. If a cold front moves in, the mercury can drop by 40°F in under an hour, and temps as low as -30°F aren’t unheard of. 

iWorx modules are used to control the building’s modulating ERV and duct furnaces for fresh-air ventilation.

The job was made easier by a Taco iWorx control system that features field-configurable sequences, yet doesn’t require programming. It allows all components to work in tandem while providing web access.

Primary heat is supplied by four, 399 MBH Triangle Tube condensing boilers and nearly seven miles of in-slab radiant tubing divided into 47 zones. Four RenewAire ERV systems supply ventilation to 42 zones per ASHRAE 62.1. 

Sharing main trunk lines with the ERV units are propane-fired Modine duct furnaces which further temper makeup air during the winter. Given Creede’s mild summers and lack of humidity, cooling is provided only to one meeting room and an IT closet.

Remote controls

“The advantage of an iWorx system hits home for the building owner out here in the boondocks,” said Shawn Metzler, controls superintendent at Rogers & Sons. “When they realize they don’t need a separate controls contractor — at the time of installation or going forward — they see value. Because of our use of iWorx controls, we’re a one-stop-shop: HVAC and controls.”

“There’s no code to write,” continued Metzler. “You don’t need special tools or software.  Compared to a DDC system, you eliminate a lot of hours typically spent programing and commissioning.”

Pre-programmed modules are used on equipment, zone valves and dampers throughout the building. All components report back to a touch-screen LCI (local control interface) in the boiler room. Each module self-identifies on the network when first turned on. 

“Through the design phase, we used Taco’s iWorx Selection Wizard, which gives us a bill of material, sequence of operation, wiring diagram and submittals,” said Metzler.

Another selling feature for the school was that the first cost for an iWorx system is the last cost. There are no continuing fees associated with it and software upgrades are free. Proprietary systems, including LON, BACnet and Modbus, interface easily with iWorx.

“If we have any technical questions, we call Peter Moore, at McCoy sales, or directly to Taco support,” said Metzler. “Both have answered questions on the weekend.”

Radiant for the Rockies

To satisfy the building’s 1.2 million BTU load, the well-insulated slab contains three-quarter-inch Uponor PEX at 12-inch centers.  Each classroom and common area has a small iWorx thermostat linked to the main network.

“The individual zones will ‘vote’ upon calling for heat,” said Metzler. “Because these zones are small, we’ve set up the controls so that any single zone can’t fire the boilers.  Only numerous T-stats calling simultaneously will cause one or more of the boilers to start running.”

The four wall-hung boilers lead, lag and rotate, while providing 25 percent redundancy: a necessary insurance measure for a facility with epic winters and a half-day drive from the nearest supply house. 

Despite more time and effort, dozens of remote manifolds were hidden above the ceiling to eliminate access doors. Each stainless steel manifold utilizes a low-kW Taco Zone Sentry zone valve. 

When it came time to fill the radiant system in the winter months, technicians found themselves without water. The ground was frozen solid, so utilities couldn’t be run to the building. They called the fire department, where Robert Hosselkus, the Sheriff’s brother, serves as Fire Chief.  Before long, a red tanker truck showed up at the site.    

“It was the first time I’ve purged a system with a fire truck,” said Ellis. “It was the fastest fill we’ve seen!”

“If ever there was a place for outdoor reset control, this is it,” he continued. “Radiant supply temperatures will be anywhere between 80°F and 120°F. I think the record low in Creede is -45°F.”

Shawn Metzler finishes wiring controls for the DOAS.

For the same reasons, the school’s DOAS (dedicated outdoor air system) is robust and flexible. 

DOAS: ERV with a sidekick

Two mechanical mezzanines house a variety of ventilation components which are completely independent of the hydronic heating system. 

Four RenewAire ERVs serve various parts of the building. Two smaller units capable of up to 2,500 CFM each are used, as are two units with capacities of 4,000 CFM. With VFD-powered fans, the units can modulate as low as 15 percent.

“A pre-programmed occupancy schedule ensures constant minimum ventilation while the building is in use,” said Ellis. “A VAVD iWorx module gathers data from CO2 sensors in each room. When the level reaches 1,000 PPM, the ERVs ramp up accordingly.”

To supplement each ERV, Rogers & Sons installed a separated-combustion Modine duct furnace.

“When the outdoor air temperature falls below the ERVs’ ability to maintain supply air at 69°F, the Modine furnaces pick up the slack,” explained Metzler. “We expect this to occur when outdoor temps hit 10°F.” 

The duct furnaces were selected based on their flexibility, both in regard to installation and heat input. The separated combustion units supply a temperature rise anywhere between 20°F and 100°F, can modulate between 40 and 100 percent, and are available in sizes between 75 and 400 MBH.

Installed downstream of the ERV core, the modulating duct furnaces will fire only high enough to bring the makeup air to neutral building temperature. With this setup, efficient ventilation is provided without raising the load on the radiant system at all.

Against the grain

Despite the marathon commute, the debilitating cold in early stages of the project, and architectural considerations that made the job more complex, Rogers & Sons finished their work three weeks ahead of schedule. The building was ready for students in the beginning of the 2015/2016 school year.

“This job went smoothly because of two key factors,” said Ellis. “Careful preparation and familiarity with the products we selected.” Rogers & Sons has been serving the far reaches of Colorado since 1978 and has grown accustomed to the challenges that the big, wild territory can conjure up. 

“Creede needed a new school,” said Hosselkus. “The old one is a log, and built in 1952.  Some of the wood has rotted beyond repair. The new school is plenty big and fancy enough for Creede, but it looks like it’ll serve the town well for a mighty long time.”

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