HVAC_System_Description.pdf

Project Title: Retro-Commissioning Repairs Project Location: USDA-ARS, National Soil Erosion Lab (NSERL)

175 University St.

West Lafayette, IN

Date: 26 June 2017

HVAC SYSTEM DESCRIPTION

INTRODUCTION

The purpose of this document is to provide a description of the existing conditions of the mechanical equipment at the USDA-ARS, National Soil Erosion Laboratory (NSERL) in West Lafayette, Indiana.

CHILLED WATER SYSTEM

Equipment Tag 90 ton Chiller (Trane) Chilled Water Pump #1 (Taco) Chilled Water Pump #2 (Taco) Chilled Water Pump #3 (Taco) Chilled Water Pump #1 (Taco) Chilled Water Pump #4 (Taco)

The chilled water system consists of a 90 ton Trane RTUD Series R chiller, a Trane CAUJ-C40 Series R air cooled condensing unit, and four chilled water pumps that circulate chilled water throughout the building.

The chilled water equipment is located in the southwest corner of the building’s basement.

The chilled water system serves a cooling coil in each of the three air handling units: AHU-1, AHU-3, and

AHU-4.

The chilled water system was installed in 2010 and is in good operating condition.

The building has no refrigerant alarm installed to protect staff and service personnel from refrigerant leaks. The Indiana Mechanical Code requires that not only the room have a working refrigerant alarm, but also have the alarm interlocked with exhaust system so that in the case of an emergency the exhaust fan will cycle on to allow for safe egress of any individual in the space. The basement exhaust fan is currently controlled by a thermostat with a setpoint of 80 degrees F. The chilled water pumps are constant speed pumps and are not controlled by a variable frequency drive.

HEATING WATER SYSTEM

Boiler B-1 (lead) Boiler B-2 (backup)

175 University St.

Boiler 1 Recirculating Pumps #1 and #2 Boiler 2 Recirculating Pump #1 and #2 Heating Water Pump #1 Heating Water Pump #2

The heating water system consists of two 1500 Mbh Lochinvar SBN 1500 condensing boilers that operate off of natural gas. Two small recirculation pumps are connected to each boiler. In addition to the recirculation pumps there are two Taco pumps that circulate heating water throughout the building.

The heating water pumps are constant speed pumps and are not controlled by a variable frequency drive.

The heating water system is located in the southeast corner of the building’s basement.

The heating water system was installed in 2010, and is in good operating condition.

Boiler B-1 and B-2 Building Heating Water Pumps #1 and #2

UNIT HEATERS

Unit Heater #1 Unit Heater #2 Unit Heater #3 Unit Heater #4 Unit Heater #6 Unit Heater #6 Unit Heater #7 Unit Heater #8 Unit Heater #9 Unit Heater #10 Unit Heater #11 Unit Heater #12 Unit Heater #13 Unit Heater #14 Unit Heater #15 Unit Heater #16

175 University St.

Cabinet Unit Heater #1 Cabinet Unit Heater #2 Cabinet Unit Heater #3 Cabinet Unit Heater #4 Cabinet Unit Heater #5

There are sixteen (16) unit heaters that are located in various locations throughout the building.

Seven (7) unit heaters are installed in the interstitial space over the office and laboratory areas. The unit heaters are controlled by two thermostats in the interstitial space. The units do not have control valves and therefore have heating water continuously circulating even when heating is not required.

Unit Heater without Control Valve

RADIANT HEATERS

Radiant Heating Panels – North Zone Radiant Heating Panels – East Zone Radiant Heating Panels – South Zone

The building has three zones of radiant heating panels: a north zone, an east zone, and a south zone.

The north zone consists of nineteen (19) radiant heating panels. The east zone consists of fourteen (14) radiant heating panels. The south zone consists of twenty-one (21) radiant heating panels. Each radiant heating panel zone has a three-way control valve. However each zone has heating water flowing through the radiant panels continuously even when heating is not required.

Typical Radiant Heating Panel

175 University St.

MAJOR AIR HANDLING SYSTEMS

AHU-1

AHU-2

AHU-3

AHU-4

AHU-5

AHU-1 is a variable volume air handling unit with separate return fan. This unit is located in the northeast mechanical room, and serves offices and laboratories. The original drawings indicate this unit delivers 15,600 cfm total supply air with 7,500 cfm outdoor air (48%). The unit consists of a pre-heat coil, a cooling coil, and a steam humidifier. The chilled water cooling coil was designed to provide approximately 73 tons of cooling. This air handling system was installed with a duct mounted direct steam injection humidifier, rated at 300 lbs./hour, that was replaced with an electric humidifier in 2009.

This air handling unit serves forty-one terminal boxes, nine of which have re-heat capability. The unit shows signs of corrosion around the coil sections, which may be due to a problem in removing condensation through the drain pan, past coil leaks, or inadequate casing insulation. Although the AHU was designed to deliver 15,600 cfm, the sum of all room requirements is 18,000 cfm. This is a leading cause of why many of the building spaces are not receiving enough supply air. The design supply air velocity is 3,151 fpm which is a limiting factor in delivering additional airflow. The ductwork is undersized for the air handling unit.

The overall building pressure was documented as -0.05”. Reduced fresh air intake airflow also results in negative building pressure relative to the outdoors. Exhaust fans serving restrooms, laboratory hoods, equipment rooms, etc. force a large volume of air out of the building. Air handling units should provide make up for the exhaust air plus a small offset to pressurize the building.

AHU-1 and Electric Humidifier

AHU-1 is operating, but is past its service life.

The facility staff has stated that during peak cooling load, AHU-1 struggles to maintain 55ºF discharge air temperature. The return fan is very noisy and is in need of repair.

AHU-2 was designated to be the air handler for a future second floor addition. This addition was never built, and no air handling unit exists with that tag number.

175 University St.

AHU-3 is a variable volume single zone air handling unit. This unit is located on the mezzanine of the Hydrology lab, and serves the Hydrology lab. The original drawings indicate this unit delivers 7,200 cfm total supply air with 1,230 cfm outdoor air (17%). The original configuration included only a heating coil, but has had a chilled water cooling coil added in the late 1980’s. AHU-3 is controlled by a thermostat and is not connected to any terminal boxes.

AHU-3

AHU-3 is past its service life. AHU-3 is operated in a very dirty environment. This air handler uses bag filters and has no static pressure sensor to indicate when the filters are dirty.

AHU-4 is a variable volume air handling unit. This unit is located on the mezzanine of the Hydrology lab, and serves Machine Work Area, Wood and Plastic Area, and adjacent office. The original drawings indicate that this unit delivers 2,000 cfm total supply air with 400 cfm outdoor air (20%). The unit includes a pre-heat coil and a chilled water cooling coil. AHU-4 is controlled by a thermostat and is not connected to any terminal boxes.

AHU-4

AHU-4 is past its service life. AHU-4 is operated in a very dirty environment. This air handling unit does not have a static pressure sensor to indicate when the filters are dirty.

AHU-5 is located in the basement, and was intended to serve as a glycol heat recovery unit. The original drawings indicate that this unit delivers 2,500 cfm total supply air with 2,500 cfm outdoor air (100%).

AHU-5

175 University St.

The facility staff stated that this equipment has not been operated, and has requested that it and all associated equipment be removed from the building.

TERMINAL UNITS

Equipment Tag Equipment Tag Terminal Box #1 Terminal Box #22 Terminal Box #2 Terminal Box #23 Terminal Box #3 Terminal Box #24 Terminal Box #4 Terminal Box #25 Terminal Box #5 Terminal Box #26 Terminal Box #6 Terminal Box #27 Terminal Box #7 Terminal Box #28 Terminal Box #8 Terminal Box #29 Terminal Box #9 Terminal Box #30 Terminal Box #10 Terminal Box #31 Terminal Box #11 Terminal Box #32 Terminal Box #12 Terminal Box #33 Terminal Box #13 Terminal Box #34 Terminal Box #14 Terminal Box #35 Terminal Box #15 Terminal Box #36 Terminal Box #16 Terminal Box #37 Terminal Box #17 Terminal Box #38 Terminal Box #18 Terminal Box #39 Terminal Box #19 Terminal Box #40 Terminal Box #20 Terminal Box #41 Terminal Box #21

The building has a total of forty-one (41) variable air volume terminal boxes that serve the offices and laboratories. Each box is controlled by a thermostat in the office or laboratory space. The terminal boxes are located in the interstitial space.

VAV Terminal Box

175 University St.

The terminal units, with the exception of one unit, are past their respective service life. The majority of the terminal units are not providing adequate cooling to the occupied spaces. The functional testing that was completed on the terminal boxes has shown that some of the control valves on the reheat coils are either not working correctly or not working at all.

EXHAUST SYSTEMS

Exhaust Fan #1 Exhaust Fan #2 Exhaust Fan #3 Exhaust Fan #4 Exhaust Fan #5 Exhaust Fan #6 Exhaust Fan #7 Exhaust Fan #8 Exhaust Fan #9 Exhaust Fan #10 Exhaust Fan #11 Exhaust Fan #12 Exhaust Fan #13 Exhaust Fan #14 Exhaust Fan #15

The building has fifteen (15) exhaust fans.

The building general exhaust fan is located in the small mechanical room located on the southwest mechanical room. The fan does not run continually, and is controlled by AHU-1 status.

The northeast restroom group is served by a fan located on the roof over the main entry. This fan runs continually and is not connected to the BMS.

The southwest restroom group is served by a fan located on the roof near the southwest corner of the building. This fan runs continually and is not connected to the BMS.

The Hydrology Lab has a large exhaust fan located on the roof. This fan is only run occasionally, and is controlled by an electrical disconnect in the Hydrology Lab. This fan is not connected to the BMS.

The welding hood in the machine room has a large exhaust fan located on the roof of the Hydrology Lab.

This fan is only run occasionally, and is controlled by an electrical disconnect in the machine room. This fan is not connected to the BMS.

175 University St.

There is a dedicated exhaust fan for the walk in fume hood in Laboratory 124. The fan is located in the interstitial space and is exhausted outside by means of ductwork through the roof. This exhaust fan is controlled by a switch on the wall in Laboratory 124. This fan is not connected to the BMS.

There is a dedicated exhaust fan for the snorkel exhaust system in Laboratory 124. The fan is located in the interstitial space and is exhausted outside by means of ductwork through the roof. This exhaust fan is controlled by a switch on the wall in Laboratory 124. This exhaust fan is not tied to the BMS.

There is a dedicated exhaust fan for the fume hood in Laboratory 147. This fan is located on the roof of the Hydrology Lab, and is controlled by a switch on the fume hood. This fan is not meeting an exhaust velocity of 3000 fpm. This fan is not connected to the BMS.

There is a dedicated exhaust fan for the fume hood in Laboratory 148. This fan is located on the roof of the Hydrology Lab, and is controlled by a switch on the fume hood. This fan is not meeting an exhaust velocity of 3,000 fpm. This fan is not connected to the BMS.

There is a dedicated exhaust fan for the per chloric acid fume hood in Laboratory 148. This fan is located on the roof, and is controlled by a switch on the fume hood. This fan is not meeting an exhaust velocity of 3,000 fpm. The associated stack height of this exhaust fan does not meet the minimum height of 10’-0”. This fan is not connected to the BMS.

There is a dedicated exhaust fan for the fume hood in Laboratory 149. This fan is located on the roof of the Hydrology Laboratory, and is controlled by a switch on the fume hood. This fan is not meeting an exhaust velocity of 3,000 fpm. This fan is not connected to the BMS.

The Soil Grinding Laboratory has an exhaust fan located on the roof. This fan is controlled by a switch on the mezzanine in the Hydrology Laboratory. This fan is not connected to the BMS.

The Soil Grinding Laboratory hood has an exhaust fan located on the roof. This fan is controlled by a switch on the wall. This fan is not connected to the BMS.

The Soil Storage room has an exhaust fan located on the roof. This fan is controlled by a switch on the wall. This fan is not connected to the BMS.

There is an exhaust fan located in the basement that is exhausted outside by means of ductwork through the roof. This fan is controlled by a thermostat in the basement. This fan provides outside air to the basement if the room temperature reaches the setpoint of 80º F. This fan is not connected to the

BMS.

175 University St.

Fume Hood Exhaust Fans Restroom Exhaust Fan

The exhaust fans are past their service life. The exhaust fans are operating but are in need of maintenance.

LABORATORIES

The building has an arrangement of eight (8) laboratories.

Laboratory 124

Room 124 is a Soils Laboratory uses the same HVAC system as the rest of the facility. This laboratory has a walk in fume hood and two snorkel exhausts that operate off of switches on the wall. There is equipment that runs continuously that has exhaust routed directly to one of the snorkel exhausts. The laboratory will only meet the ARS air change rate requirement if the exhaust is turned on. Air flow from the laboratory to adjacent spaces is positive. This laboratory has a makeup air unit with humidifier that is located on the roof.

There is a LM Air walk in fume hood in Laboratory 124 which was installed in 2005. The fume hood is controlled by a switch on the wall. The fume hood does not have an audible alarm if the exhaust fan fails.

There are two snorkel exhaust arms in Laboratory 124 which were installed in 2005. The snorkels each have a manual shutoff damper. The snorkels are controlled by a switch on the wall. The snorkel exhausts do not have an audible alarm if the exhaust fan fails.

Per Chloric Acid Fume Hood Lab 149 Fume Hood

175 University St.

Laboratory 124A

Laboratory 124A is a Soils Laboratory that uses the same HVAC system as the rest of the facility. The laboratory does not meet the ARS air change rate requirement. Air flow from the laboratory to adjacent spaces is positive.

Laboratory 125

Laboratory 125 is a Hydraulics Laboratory that has its own dedicated HVAC system. The laboratory does not meet the ARS air change rate requirement. Air flow from the laboratory to adjacent spaces is positive.

Laboratory 127

Laboratory 127 is a Hydrology Laboratory that uses the same HVAC system as the rest of the facility.

The laboratory meets the ARS air change rate requirement. Air flow from the laboratory to adjacent spaces is positive.

Laboratory 147

Laboratory 147 is that uses the same HVAC system as the rest of the facility. Laboratory 147 is comprised of three rooms: Room 135 Soil Lab-B, Room 137 Soil Lab-A, and Room 147 Sample Prep. Each room was tested individually for ARS air change rate requirements. Room 135 meets the ARS air change rate requirement. Room 137 meets the ARS air change rate requirement. Room 147 meets the ARS air change rate requirement if all exhaust is turned on. Room 137 has equipment that when in use puts off excessive heat, and should be ducted outside. Air flow from the laboratory to adjacent spaces is positive.

There is a Labconco fume hood in Laboratory 147 which was original to the building. The fume hood is controlled by a switch on the unit. The fume hood does not have an audible alarm if the exhaust fan fails.

There is a Baker bio-safety cabinet in Laboratory 147. The bio-safety cabinet recirculates air inside of Laboratory 147. There is a pressure differential sensor on the front of the bio-safety cabinet. The bio safety cabinet is controlled by a switch on the front of the unit. The bio-safety cabinet does not have an audible alarm if the unit fails.

Laboratory 148

Laboratory 148 is a Soil Physics/Chemistry Lab that uses the same HVAC system as the rest of the facility.

The laboratory meets the ARS air change rate requirement only if all exhaust is turned on. Air flow from the laboratory to adjacent spaces is positive. Laboratory 148 has a makeup air supply fan tied to the Labconco fume hood.

175 University St.

There is a Labconco fume hood in Laboratory 148 which was original to the building. The fume hood is controlled by a switch on the unit. The fume hood does not have an audible alarm if the exhaust fan fails.

There is a Hamilton per chloric acid fume hood in Laboratory 148 which was original to the building. The fume hood is controlled by a switch on the unit. The unit is not used for per chloric acid. The fume hood does not have an audible alarm if the exhaust fan fails.

Laboratory 149

Laboratory 149 is a General Soil Physics Laboratory that uses the same HVAC system as the rest of the facility. The laboratory does not meet the ARS air change rate requirement. Air flow from the laboratory to adjacent spaces is positive.

There is a Labconco fume hood in Laboratory 149 that was installed in 2009. The fume hood is controlled by a switch on the unit. The fume hood does not have an audible alarm if the exhaust fan fails.

Laboratory 170

Laboratory 170 is designated as a Thin Soils Laboratory that uses the same HVAC system as the rest of the facility. The laboratory does not meet the ARS air change rate requirement. Air flow from the laboratory to adjacent spaces is positive.