2026-CEMIRT Report of Visit.pdf

Air Force Civil Engineer Center Civil Engineer Maintenance, Inspection & Repair Team

REPORT OF VISIT

1. Organization Visited: 47th CES, Laughlin AFB, TX

2. Dates of Visit: 8 – 30 June 2026

3. Purpose of Visit: CEMIRT assistance was requested in evaluating the Heating, Ventilating, and Air Conditioning (HVAC) systems at the Fuels Laboratory (Building 8), Base Library

(Building 223), and a Runway Support Building (Building 1776).

4. Individuals Making Visit:

Mr. George Burns HVAC Equipment Specialist AFCEC/COMH

Mr. Dustin Latham HVAC Equipment Specialist AFCEC/COMH

5. Personnel Contacted:

Lt Col Benjamin Johnson CES Commander 47 CES/CC

Capt Tia Massa Ops Flt Commander 47 CES/CEO

Ms. Karla Hernandez Ops Flt Deputy CC 47 CES/DC

Ms. Antionette Trevino Engineering Flt Chief 47 CES/CEN

Ms. Cynthia Goszeski Project Manager 47 CESCEN

Mr. Lazaro Campos R&O HVAC Lead 47 CES/CEOM

Mr. Walter Wilridge Deputy Ops Manger Chugach

6. General: CEMIRT HVAC assessments were requested and performed at the following three facilities:

Building 8 contains a specialized, 300-square-foot, Type C+ fuels laboratory that is supported by an independent environmental control system. Ambient temperature and humidity levels are regulated by a standalone, 5-ton Daikin packaged HVAC unit, complemented by a dedicated exhaust fan designed to manage negative pressure and regulate critical airflow within the conditioned space. To preserve personnel safety during fuel testing and chemical analysis, the facility is equipped with a high-efficiency ventilation hood cabinet, enabling technicians to safely execute testing procedures while exhausting hazardous vapors.

Building 223 is a 9,000-square-foot, multi-use facility that accommodates the Base

Library, the Air Force Career Advisors' offices, and dedicated training classrooms. To optimize operational energy efficiency, the facility is designed with a closed-loop geothermal HVAC system. This system circulates tempered condensing water to 16 localized Heat Pumps (HP) zoned throughout the building, as well as to a centralized Energy Recovery Unit (ERU) that pre-conditions and distributes the mandated minimum volume of outdoor air.

Building 1776, known as the Runway Control Structure, is a 230-square-foot facility engineered to allow flight instructors to monitor and evaluate pilots during active training exercises. The lower-level houses vital communications and control systems, while the second-story observation deck provides instructors and observers with a direct line of sight and communications link to pilots on the runway. Climate control is delivered by two, 4-ton HPs supplying the second floor, complemented by a single 3-ton HP dedicated to the first floor.

7. Findings, Actions Taken, and Recommendations: Fuels Laboratory (Building 8)

(Building 8, Fuels Lab)

a. Finding: CEMIRT’s technicians recorded the laboratory's Relative Humidity (RH) at approximately 73.7% at an ambient temperature of 68.6°F, equating to a dewpoint of 75.5°F.

These environmental conditions exceed the established Unified Facilities Criteria (UFC) standards for Precision Measurement Equipment Laboratories (PMEL) and fuels laboratories.

The UFC mandates a maximum allowable dewpoint of 55°F and a standard operating temperature maintained at 73°F ±5°F.

Action Taken: The operational parameters of the Daikin unit were checked and the indoor temperature setpoint was then adjusted from 68°F to 71°F, ultimately establishing a final setting of 70°F for the conditioned space. Additionally, the dehumidification control target was modified from a 55°F dewpoint setting to a more stringent 50°F threshold. Subsequent monitoring of the system's performance over several consecutive days demonstrated that the unit successfully stabilized the space, maintaining both temperature and RH within the mandated UFC operational parameters.

b. Finding: The Variable Frequency Drive (VFD) for Exhaust Fan (EF) 2 was not functioning, thereby rendering EF-2 inoperable.

Action Taken: CEMIRT technicians collaborated with base controls technicians to try and diagnose the VFD issue affecting EF-2. This included testing the incoming electrical power, confirming that the fan and motor rotated freely by hand, and assessing the mechanical drive belt to ensure its condition was acceptable. Additionally, the team attempted local system operations and executed standard troubleshooting protocols to restore functionality.

Recommendation: Replace the failing VFD. Upon installation, the technical team must program the drive, verify all motor parameters, and perform thorough operational testing to safely return EF-2 to reliable, continuous service.

c. Finding: The existing laboratory exhaust intake is currently configured as a ceiling-mounted fixture. However, the facility's classification was verified as a Type C+ laboratory, which, according to UFC 4-310-03 standards, requires the exhaust intake to be positioned no higher than 6 inches off the floor surface.

Recommendation: Reconfigure and relocate the exhaust intake ductwork to bring the laboratory into full compliance with UFC installation requirements.

d. Finding: Air pressure within the laboratory space was measured as positive relative to both the adjacent office spaces and the outdoors. This positive pressurization violates UFC 4-

310-03 standards, which mandate that the laboratory maintain slightly negative air pressure relative to adjacent office spaces to prevent hazardous fuel vapors from migrating into administrative work areas.

Action Taken: Measured and recorded the differential air pressure relationships both from the laboratory room to the main building interior, and from the laboratory room to the outdoors, evaluating these gradients under multiple mechanical operating configurations.

Recommendation: This pressurization deficiency should be resolved once the VFD for

EF-2 is replaced, allowing the exhaust fan to operate according to its original engineering design.

e. Finding: The high-pressure cutoff switch for the refrigerant discharge on the Daikin unit's compressor has shorted out. This electrical fault completely bypasses the primary safety cutoff mechanism, creating a severe operational hazard. In the absence of this functional safety control, the system is incapable of executing an automatic shutdown if refrigerant pressures exceed safe operational thresholds, which could ultimately result in catastrophic compressor failure or ruptured refrigerant lines (see photo below).

(Shorted Sensor)

Recommendation: Replace the shorted high-pressure cutoff switch immediately to restore the environmental control unit’s critical safety protocols. Once the new switch is installed, technicians must verify that it is calibrated to the manufacturer's specifications and perform a functional test of the safety shut-off sequence prior to returning the Daikin unit to normal, unattended service.

f. Finding: The exterior exhaust stack is currently missing its protective weather cap.

Without this protective barrier, the open vertical pipe is fully exposed to environmental elements, allowing rainwater, dirt, ambient debris, and potentially nesting wildlife to enter the exhaust ductwork. Moisture and debris intrusion into the ventilation system can result in localized water pooling, premature metal corrosion, and severe mechanical or electrical degradation of the connected exhaust fan components (see photo below).

(Missing Weather Cap)

Recommendation: Procure and install a properly sized, weather-resistant exhaust cap.

Ensure the new cap is securely fastened and specifically engineered to prevent moisture and pest infiltration while also avoiding any restriction on the system's required exhaust airflow velocity.

8. Findings, Actions Taken, and Recommendations: Base Library (Building 223)

(Building 223, Base Library)

a. Finding: The water temperature within the closed-loop geothermal condensing system was significantly elevated. Although the original engineering design specifies an optimal condensing water temperature of 85°F, the geothermal loop was operating at temperatures ranging between 105°F and 115°F.

Action Taken: Evaluated the operation of the water distribution pumps to ensure they were performing within the mandated parameters. The pumps are configured to operate at 100% capacity using a lead-lag control scheme, which dynamically activates each pump as system demand dictates. Every individual pump is rated to deliver a volumetric flow rate of 99 gallons per minute (GPM); a minimum system flow rate of 89 GPM is required to successfully meet the collective operational demands of all the building's climate control equipment.

Recommendation: Commission a comprehensive engineering study to evaluate the thermal capacity of the geothermal loop and determine if the existing well field is adequately sized to support the facility's connected load. This study should assess integrating supplemental heat rejection technologies such as a fluid cooler, cooling tower, or an expanded ground loop to effectively dissipate excess thermal energy from the condenser water system. Concurrently, maintenance personnel must ensure that the entire geothermal loop and all associated well points are thoroughly flushed to remove accumulated debris. Finally, updated as-built documentation must be generated for the geothermal infrastructure, and all historical system repairs must be verified.

b. Finding: The PU-1 condenser water pump was found to be mechanically seized and failed to actuate when commanded by the system controls. The mechanical distribution loop is designed to run on a lead-lag configuration where only one pump operates at a given time, utilizing an automated sequence to alternate workloads between the primary and secondary units

(see sample photo of condenser water pump below).

(Operational PU-2 Condenser Water Pump)

Action Taken: CEMIRT technicians removed the top cover from the pump and were able to free it up using light pressure. It appeared that it hadn’t run in a long time allowing it to seize. A test run verified that the pump was performing in accordance with standard operational parameters.

Recommendation: Continue to actively monitor the automated pump alternation sequence to verify that the lead-lag control logic functions correctly and balances operational runtime between the units.

c. Finding: The ERU was found to be completely shut down and offline.

Action Taken: Following consultations with shop personnel, CEMIRT technicians learned that the ERU had been offline for approximately two years due to persistent system shutdowns, mainly triggered by high refrigerant discharge pressure. This operational issue was ultimately caused by elevated condenser water temperatures within the geothermal loop. Technicians successfully restarted the unit, restoring the system to full operation and ensuring that the facility receives the mandated volume of fresh outdoor air. The ERU has now been operating continuously for two weeks without further disruption.

Recommendation: Systematically verify the ERU's sequence of operations and continue to monitor its mechanical performance. Maintenance personnel must ensure that the ERU remains fully operational to deliver the outdoor air ventilation rates required for the facility.

Additionally, technicians must evaluate whether previous high-head-pressure shutdown events were primarily caused by elevated geothermal loop water temperatures rather than any inherent mechanical failures within the ERU itself.

d. Finding: HPs 6, 7, and 9 were verified as non-operational and out of service.

Action Taken: Discussions were conducted with base maintenance personnel, who indicated that replacement parts had already been requisitioned to repair the non-functioning

HPs. While present at the facility, maintenance personnel successfully repaired HP-9, restoring it to active service.

e. Finding: The circulation fan integrated into HP-5 is significantly undersized for the specific zone it is tasked with heating and cooling. Although the blower motor is rated for a maximum output of 350 Cubic Feet per Minute (CFM), the served zone encompasses 475 square feet of floor space and features two exterior walls oriented towards the South and West.

Consequently, this space experiences high, continuous solar heat gain throughout the peak hours of the day. The facility's initial thermal load calculation should have accounted for this intense solar exposure by applying a 1.2 to 1.5 safety and exposure multiplier, which would have resulted in an appropriate engineering design flow rate of 550 to 700 CFM.

Recommendation: If this specific zone remains uncomfortably warm after completing remediation efforts to lower the geothermal condensing water temperature to its design target of

85°F, it may be necessary to buy and install a larger HP unit to adequately condition the space.

9. Findings, Actions Taken, and Recommendations: Runway Control (Building 1776)

(Building 1776, Runway Control

a. Finding: Elevated humidity levels were observed and recorded throughout the facility.

Recommendations: During future renovations of facilities like building 1776, engineering teams must ensure that a dedicated dehumidifier is installed on the lower floor to regulate humidity levels and stabilize the environment at approximately 50% relative humidity.

Concurrently, facility maintenance should systematically seal all structural holes, cracks, and penetration points to prevent outdoor moisture infiltration.

b. Finding: Airflow diffusers serving the lower level were found to be completely closed off on the second-floor ductwork distribution system (see photo below).

(Remove and Seal These Diffusers)

Recommendation: During future renovations, design teams must ensure that the exterior surfaces of all ductwork are thoroughly insulated. Additionally, contractors should eliminate the lower-level air diffusers that currently feed off the ductwork distribution system designated for the second floor.

b. Finding: Significant accumulations of efflorescence salts were observed on the interior concrete block walls, indicating ongoing moisture migration through the building envelope (see photos below).

(Efflorescence On First Floor Walls)

Recommendation: Adhere strictly to the professional remediation guidelines outlined by

Mr. Charles Boulian, a structural engineer with the Air Force Civil Engineer Center (AFCEC), for the mitigation and removal of efflorescence salts from the wall surfaces. The scope of work must include the complete removal of all existing interior wall coatings, as well as the systematic elimination of any crystalline salt deposits discovered beneath the current paint layers. The following steps should be utilized:

• Dry Removal Process: Initiate the remediation by utilizing a stiff-bristled, non-metallic brush or scraper to dislodge flaking paint and loose crystalline salt deposits. This procedure must remain strictly dry; introducing water will dissolve the soluble salts, facilitating their re-absorption into the porous concrete matrix.

More stubborn structural accumulations may be removed utilizing a wire brush.

• Chemical Cleaning (If required): Should mechanical brushing prove insufficient to eradicate all efflorescence, technicians may apply a mild acidic solution (such as diluted vinegar) or a more aggressive agent (such as muriatic acid) to dissolve the residual mineral deposits. Following any acid application, the chemically treated surface must be thoroughly rinsed and neutralized with an alkaline solution (e.g., a baking soda mixture) to restore a balanced surface pH. Finally, the area should be pressure-washed utilizing a Trisodium Phosphate cleaning agent.

• Priming & Coating: Prepare the interior masonry surface by applying a specialized, efflorescence-resistant primer, such as Sherwin-Williams Loxon

Concrete & Masonry Primer-Sealer or an approved equivalent product.

Subsequently, finish both the exterior and interior wall assemblies with a high-build, elastomeric acrylic coating (e.g., Sherwin-Williams Loxon XP or equivalent) to establish a flexible, waterproof envelope that is highly resistant to ultraviolet (UV) degradation. Alternatively, an industrial-grade interior acrylic formulated with zero volatile organic compounds (VOC) such as ProMar 200 High

Performance (HP) Zero VOC or an approved equivalent may be applied exclusively to the interior walls

10. General: Personnel attending the formal out-brief on 29 June 2026, were fully briefed on the above-mentioned findings, actions, and recommendations. If any questions should arise or further assistance is necessary, please don’t hesitate to contact Mr. Patrick Ross, DSN 523-6906 or by email: patrick.ross@us.af.mil.

PATRICK M. ROSS, NH-03, DAF

Chief, CEMIRT HVAC Branch