SOW_LWM HVAC.pdf

HVAC REPLACEMENT 10/27/2023

AIR TRAFFIC CONTROL TOWER Lawrence, MA

STATEMENT OF WORK

REPLACE HVAC UNIT FAA

Air Traffic Control Tower (LWM) Lawrence, MA

1. OBJECTIVE. Replace Heating, Ventilating, and Air Conditioning (HVAC) units throughout the facility including cab rooftop unit and multiple package terminal air conditioner (PTAC) units. Provide and install three electric unit heaters (EUH). Apply protective elastomeric roofing coat to protect the existing roofing system on the ATCT cab and the base building.

2. FACILITY. The project is located at the following address:

A. Air Traffic Control Tower (LWM) - 492 Sutton Street, North Andover, MA 01845

3. GENERAL. The Contractor must furnish all labor, equipment, and materials for replacement the HVAC equipment and the roof rehabilitation at the Air Traffic Control Tower in Lawrence, MA. The following items are a summary of the project and provided solely for describing the general nature of the work. The contractor is advised that this is a fully operational facility, and any unscheduled interruptions may cause aircraft accidents and loss of life. The facility shall remain operational throughout the entire contract unless a coordinated shutdown is scheduled. The contractor is responsible for accomplishing all items of work identified in the applicable drawings, specifications, and provisions of the contract. In general, the work consists of the following (Contractor must provide and install the following):

4. SCOPE OF WORK.

A. DEMOLITION

1. Demolish existing rooftop unit and existing vibration isolation curb

2. Demolish existing supply flex ductwork

3. Demolish (1) window ac unit in fourth floor equipment room

B. ATCT HVAC replacement

1. Provide and install new roof top unit (Trane, or approved equal) must be 8.5 ton with a factory installed 27

KW electric heater

2. Provide and install a new vibration isolation curb

3. Provide and install new thermostat for rooftop unit (add opaque thermostat cover)

4. Provide and install supply duct work from the rooftop unit to distribution boxes

5. Provide continuous temporary cooling and heating throughout construction period

6. Provide and install new copper condensate line with a trap (clean roof drains)

7. Clean all remaining duct work and linear slot diffusers using a NADCA certified company

8. Provide testing, adjusting, and balancing (TAB) to be performed on new system

9. Replace all ceiling tiles damaged during construction period, match existing

C. CAB and Base Building Roof rehabilitation

1. Repair roofing at tower shaft corners under catwalk prior to elastomeric coating

2. Replace wet insulation on base building. Patch and coat base building TPO roof with Elastomeric Coating

3. Coat ATCT roof deck and base building roof deck with elastomeric coating

4. Scrape and prep all railings on cab catwalk and cab roof, and seal with elastomeric coating

5. Coat ATCT parapet wall and cab walls above catwalk with elastomeric coating

D. Package terminal air conditioners and electric unit heater replacement

1. Provide and Install (3) PTAC units

2. Provide and install (3) EUH units

E. Equipment and workmanship warranties

1. Include HVAC manufacturer’s warranty: 5 years on compressors and coils

2. Include labor/ installation warranty: 1 year on all parts and materials

3. Include roof warranty: 20 year on new roofing systems

5. LIST OF DRAWINGS (Included as 1 attachment)

LWM -21005021-G001 COVER SHEET & INDEX SHEET

LWM -21005021-G002 GENERAL NOTES

LWM -21005021-C001 ROOF REPAIRS

LWM -21005021-D001 CIVIL DEMOLITION

LWM -21005021-D002 MECHANICAL DEMOLITION

LWM -21005021-S001 HVAC AND VIBRATION CURB

LWM -21005021-M001 MECHANICAL HVAC SCHEDULE

LWM -21005021-M002 MECHANICAL DUCTWORK DETAIL

LWM -21005021-M003 MECHANICAL HVAC DETAIL

LWM -21005021-M004 VIBRATION CURB CUTSHEET

LWM -21005021-E001 ELECTRICAL ONE LINE DIAGRAM

LWM -21005021-E002 ELECTRICAL PANEL SCHEDULE

6. MATERIALS.

A. Materials furnished by the contractor for this project shall be new, unless specified materials can be re-used.

All product to be installed to the manufacturer’s instructions.

B. Hazardous Materials. No materials supplied by the contractor for this project shall contain asbestos or lead-based materials. All SDS sheets must be provided prior to construction for all required materials.

7. SITE VISIT. Contractor must have crane operator visit site prior to submitting crane lift plan.

8. PERFORMANCE PERIOD. Complete all work within 60 calendar days of Contractor’s Notice to Proceed. Based on facility requirements, night work may be mandatory

9. MEETINGS. Attend 2 separate meetings at the facility after contract award or virtual (based on CO’s discretion) and prior to start of work. Meetings may be on different days and several days or weeks apart. All meetings are mandatory. Meetings include:

A. Preconstruction:

1. Logistics, schedule, deliveries, mobilization, etc.

2. Contractor personnel

3. Submittal approval

B. Operational Risk Management/ Mitigation

1. Personnel and facility safety requirements

2. Coordination and communication for outages

10. SECURITY. Site access is restricted. Contractor employees must be always escorted by an FAA badged employee (COR). Comply with all facility security requirements and inspections. Facility is on federal property.

A. All personnel performing work under this contract will be subject to the security requirements of the facility

11. SUBMITTALS.

A. Materials and Equipment. Provide submittal data for equipment proposed for use. Electronic portable document format (PDF) files of manufacturer’s complete performance data and descriptive literature must be submitted to the Contracting Officer (CO) for review and approval. Highlight specific model numbers, styles, and types scheduled for installation. All equipment and material that are not in accordance with the contract drawings and specifications must be specifically so noted and highlighted in the submission.

B. Material Safety Data Sheets (MSDS). The contractor must supply the COR with MSDS’s of each material 3 days before it is brought on site. The contractor must place all MSDS’s in a binder in an accessible location so that all employees on site must have access to them. The binder must be updated each time a new material is brought on site or when a material is taken off site. After submission of the MSDS, no product substitutions are allowed without prior approval from the COR.

C. Safety Plan. The contractor must be required to submit a plan, within 14 days after contract award, for maintaining a safe environment. The plan must include practices used to comply with health and safety requirements. The contractor must certify in writing that he has all appropriate safety programs which comply with all federal, state, and local regulations.

D. Accident reports: A copy of each accident report, which the Contractor or subcontractors submit to their insurance carriers, shall be forwarded through the COR to the Contracting Officer (CO) as soon as possible, but in no event later than 48 hours after the accident occurred.

E. Odor mitigation plan: Contractor must submit a plan for approval, 2 weeks prior to construction start, for maintaining odor free working environment. There must not be any openings in the building during the application of any odor generating materials. The plan must include practices to mitigation the odor from roofing materials. Plan must include but not limited to use of night work, sealing cab outdoor ventilation, and indoor odor monitoring.

12. INSTALLER QUALIFICATIONS.

A. The installing contractor shall have been engaged in the installation, service, and repair of this type of system for a minimum of 5 years. The installing contractor shall have an established working relationship with the Unit manufacturer and have all required certifications.

B. Crane operator must meet all federal, state, local, and manufacturer’s requirements to operate the crane on site. Proof of current qualification must be submitted before crane operation. Crane operation will be limited to the approved scope in the obstruction evaluation and lift plan.

C. Any work engaged in duties/ performance of rigging must be a Qualified Rigger. Employer must determine and designate in writing the qualified rigger(s) and the specific rigging tasks task for which they are qualified and provide qualifications.

D. Compliance with regulations: All work, including the handling of hazardous materials, shall comply with applicable state and municipal safety and health requirements. Where there is a conflict between applicable regulations, the most stringent shall apply.

13. PROJECT CONDITIONS

A. Full FAA Occupancy: FAA will occupy the site and existing buildings during entire project period.

Cooperate with FAA personnel during project to minimize conflicts with FAA's operations.

B. Hours of Operation:

1. The ATCT hours of operation are 6:00AM – 11:00PM. The Contractor shall coordinate all construction activities with COR to eliminate impacts that would adversely impact the functions of the Air Traffic Controllers. To preclude adversely effecting air traffic operations, it is anticipated that some construction activities will have to be accomplished at night. Night work shall be conducted from 11 PM – 6 AM for specific tasks as noted below and as directed by the FAA COR.

2. Expected night work activities are as follows:

1 Installation of materials (waterproofing) which requires a manlift operating in front of the Cab windows on the runway side of the tower. Any activity that is above the catwalk, obstructs any portion of the air traffic controllers view of the runway, produces odor/ off-gasses, or produces excessive noise for an extended period, must be done between 11 PM and 6 AM.

2 Activities that are excessively noisy such as cutting / grinding for an extended period.

3 Removal and installation of the roof and HVAC unit 4 Removal and installation of the supply and return duct work in the cab.

5 Existing grating demolition / removal unless sections can be unbolted and removed in sections

(no cutting / grinding during the day).

6 Other activities as directed by the COR.

C. Operational Risk Avoidance.

1. General. This facility provides services to assist in the control of aircraft movement, operates daytime hours, 365 days a year, and is vital to the National Airspace System. The building is densely filled with electric and electronic equipment. This facility is secured with locked interior and exterior doors. All work will be performed with the facility maintaining full operation.

2. Coordination of Work Affecting Operational Systems or Personnel. Coordinate all work that has any or may have any impact on any operational systems or personnel within the facility through the COR.

Cease and report any work that is adversely impacting the operations of the facility or personnel and immediately report impact to COR; repair or restore any portion of the operational system that has been damaged or suffered diminished performance because of the Contractor’s activities.

3. Avoid actions deemed detrimental or increasing risk to the facility’s mission, occupants, or equipment.

4. Avoid activities that create objectionable noise, release detectable odors, or generate smoke.

5. Avoid activities that raise temperature or decrease air volume in electronic equipment spaces, electrical equipment spaces and other areas that would suffer potential failures or reduced performance from such changes.

6. All space temperature and air volume changes must be scheduled and approved in advance by the COR.

7. Circuit Breakers. Circuit breakers and disconnect switches will be operated by FAA personnel only.

Contractor personnel must not operate circuit breakers or any other electrical disconnecting device. FAA will lockout/ tagout equipment to ensure personnel safety while safeguarding facility operations.

Contractor shall participate as an observer in lockout/ tagout procedures to protect contractor as well as FAA personnel. Contractor required to submit lockout/ tagout plan for approval, prior to construction.

D. Safety.

1. Perform all work safely and in accordance with the following requirements.

2. Comply with FAA Electrical Standards, FAA Safety Standards, National Electrical Code (NFPA 70), National Fire Code, OSHA, manufacturer’s recommendations, local, state, and federal regulations, other authorities having jurisdiction, and local facility requirements. FAA Standards are available on request.

3. Workers must use Personal Protective Equipment (PPE) as required by code, regulation, standard, or manufacturer’s recommendation. |

4. Operators of and heavy equipment or machinery shall be properly certified.

5. Contractor to handle refrigerant according to local, state, and federal requirements; including, but not limited to the removal, storage, and disposal of the refrigerant in the existing HVAC system. All refrigerant recover equipment as well as personnel disposing of refrigeration/ AC equipment must have required certifications. Contractor to maintain recordkeeping requirements for persons disposing of refrigerant. See EPA 40 CFR Part 82, subparts A and F.

E. Coordination and Approval.

1. Coordinate with and obtain approval from COR for work schedule, hours, and activities daily.

Coordinate high risk tasks with COR prior to work start. High risk tasks include, but not limited to outages, cutovers, crane lifts, and new unit startup.

2. Contractor must provide temporary sanitary facilities to be used by workers on site. These must remain on site for the duration of the contract. The contractor must provide their own portable shelter to be located on site. Final location will be coordinated with the local FAA staff and COR.

3. Provide a suitable dumpster for construction waste. The Contractor must have container emptied with suitable frequency so that trash does not overflow and blow around site and adjacent property.

A cover is required and must be provided on the dumpster for the refuse not to blow out. The Contractor must be responsible for the timely, legal disposal of all construction waste.

F. Drawings. The work to be accomplished is described in the statement of work. The drawings are intended to provide a general layout of the new mechanical systems and buildings areas. The contractor to maintain redline drawings throughout construction to be provided to the CO and COR at project completion.

14. CLEANUP.

A. Remove all debris, rubbish, scrap, dirt, and protective coverings from the work areas upon completion of the work shift each day. Site conditions throughout construction period will not impact site operations. The affected work areas shall be thoroughly cleaned to their original condition at the end of each work shift. Site must be returned to original condition prior to project completion. All controlled materials must have a manifest submitted with all required transportation and disposal documentation.

15. QUALITY ASSURANCE AND WORKMANSHIP.

A. All work shall be accomplished in a neat, workmanlike manner by skilled workmen regularly engaged in their respective trade resulting in an installation that is absolutely satisfactory in both function and appearance as determined by the COR.

16. WARRANTY.

A. All material, equipment, and workmanship provided in the project shall be warranted for a period of one (1) year, from date of acceptance by the COR unless noted otherwise elsewhere in contract documents.

B. Provide a (5) year warranty from HVAC manufacturer for compressors and coils.

C. Provide a (20) year warranty from roofing system manufacturer for new roofing systems.

17. HVAC UNITS.

A. Existing Unit. One Trane 8.5 ton packaged air conditioning unit (see appendix for equipment tag and pictures of existing unit). Contractor must demolish existing unit.

B. Existing Unit Removal. Remove unit from the site and dispose of or recycle properly in accordance with

EPA, state, and local guidelines. Remove existing seismic stand and curb. During construction, provide method to protect and make the roof opening watertight.

C. New Unit. Furnish and install new high efficiency 8.5 ton packaged air conditioning units with the following features, characteristics, and options. Contractor may submit equal which has been stamped by a professional engineer.

1. Basis of Design: Trane model (TSJ102A3S0K**A1C0A2B0A0B410A)

DX cooling R-410A

8.5 Ton, Dual Compressor

208-230/60/3 Unit controls: Symbio 700 No communications interface: simple thermostat 27 kW (3 Phase) electric heat (FIAEHTB3366AA heater model number) Manual outside air damper 0-50% High static motor Hinged Access Panels/ 2” inch MERV 8 filters Standard Coil with hail guard Through the base electric Unit mounted Circuit Breaker Powered convenience outlet Dehumidification coil: modulating hot gas reheat Low ambient controls (down to 0°F) Supply air smoke detector Clogged filter switch and condensate drain pan overflow switch Stainless steel condensate drain pan

2. Installation. Install rooftop unit level and square to the building on top of the roof of the cab. New package unit must sit on new vibration isolation curb and connect to existing supply/ return plenum.

Connect power with the through the bottom connection using existing power conductors and conduits.

New thermostat to be installed in the cab using new control wires in existing conduit.

3. Crane. A crane will be required to remove existing unit and install new unit on top of the cab roof. The use of crane will obstruct the view from the cab which will interfere with the operations of the tower;

crane work must be night work. Crane placement, maximum height (100 ft), loading weight, and operation will be restricted to the obstruction evaluation. Contractor to submit a standard or critical lift plane 30 days prior to crane use. Lift plan to include, but not limited to, the following:

A. Personnel: roles, responsibilities, qualification, public persons, or other trade personnel access or affected by lift

B. Area Preparation: load handling location and path of travel, blocking/cribbing, overhead lines, ground stability.

C. Load Handling Equipment Considerations: capacity, configuration, obstructions, inspection, ground support conditions

D. Load parameters: weight, center of gravity, radii, and configuration E. Rigging: type, inspection, need for softeners F. Environmental Considerations: wind, storms, precipitation, power lines in area of travel or load swing, counterweight swing area barricaded.

D. Temporary equipment.

1. Contractor must submit a plan, for approval, on providing a complete temporary solution that must provide cooling and heating throughout construction period.

1 Provide a combination of units that provide a total of 8.5 tons of cooling to the cab space without interruption of service.

2 Provide a combination of units that provide 27 Kw of heating to the cab space without interruption of service.

3 Provide all electrical and controls equipment for complete installation. Electrical service will only be provided from the circuit breakers providing power to the current CAB rooftop HVAC unit.

4 Installation and demolition of temporary solution must occur at night if installation will negatively impact operations of tower.

E. Ductwork. Contractor must demolish all existing supply ductwork including flex and hard ductwork.

1. Contractor must provide and install new insulated supply flex duct (8"), contractor must verify linear diffuser duct opening size is compatible with new flex duct. Flex duct must be externally insulated with an R-value of 6 size. Flex duct work must be supported every 3 feet using hangers. Hangers must be constructed of 1" x 22-gauge straps (or approved equal) with 1/4" rods and attached using beam clamps (hanger must be constructed with /galv. steel). Flex ductwork shape must not deform from hanger. Flex duct shall be stretched with a compression of less than 15%.

2. Contractor must provide and install new supply ductwork (34" x 12"). Ductwork must be constructed of 16-gauge galvanized steel; ductwork must be internally insulated with 1-inch duct liner with an R-value of 6 and noise reduction coefficient of 0.60. Duct work must be supported every 5 feet using hangers.

Hangers must be constructed of 1" x 18-gauge straps with 1/4" rods and attached using beam clamps (hanger must be constructed with galv. steel).

3. Each branch of supply flex ductwork must have a manual balancing damper. Dampers must be adjusted during TAB process.

4. During ductwork demolition and installation, ceiling panels in dropped ceiling may be removed. Any damaged ceiling panels must be replaced to match existing panels.

F. Cleaning. A written work plan must be submitted by a NADCA certified cleaner, which must include scope of work, means and methods, schedule, product submittals, and SDS. All existing ductwork, grilles/ registers, distribution boxes, and plenums that is to be reused shall be cleaned and sanitized. Cleaning must be after all construction activities are completed.

G. Testing. Measure airflow, supply air temperature, and return air temperature in both cooling and heating mode. Record test results. Have a third-party TAB performed on the new system. Each linear supply diffuser must provide approximately 325 cfm, by adjusting manual balancing damper in supply ductwork. Manual outdoor air damper accessory, part of rooftop unit, must be opened to approximately 5%. TAB report must include a sound level measurement Provide copy of test results to COR at time of test completion. Include copy of test reports in close out documents.

18. HVAC VIBRATION ISOLATION CURB

A. Demolish existing cab rooftop HVAC unit curb. Contractor must remove curb from the site and dispose of properly in accordance with EPA, state, and local guidelines.

B. During construction, contractor must provide a temporary cover to protect the roof penetration from weather and outdoor infiltration when existing curb is removed. Contractor must submit temporary cover plan.

C. Install new cab rooftop HVAC unit curb. Contractor must provide and install new vibration isolation curb.

Contractor must provide shop drawings for approval prior to fabrication. Contractor must fabricate curb offsite. Curb must be anchored to structural element of tower. Refer to drawings LWM-21005021-M004 and LWM-21005021-S001 for vibration isolation curb details, or approved equal that has been reviewed and stamped by a Professional Engineer.

D. Contractor must apply elastomeric coating on the flashing of the curb. Coating must be applied to meet installation requirements of roofing material manufacturer.

19. PTAC

A. Demolish existing AC units that are servicing first/ ground floor equipment room, the second-floor equipment room, and third floor equipment. Demolish all units but electrical conductors, plugs, and conduits shall be reused. Dispose of the refrigerant according to local, state, and federal requirements.

B. Contractor must provide and install a 1.25 ton through-the-wall air conditioner with 3.5 KW electric heat in first/ ground floor equipment room. Contractor must provide unit with the features, characteristics, and options shown in the air conditioner schedule; or approved equal.

C. Contractor must provide and install a .75 ton PTAC with 3.6 KWs of electric heat in the second floor equipment room. Contractor must provide unit with the features, characteristics, and options shown in the air conditioner schedule; or approved equal.

D. Contractor must provide and install a .75 ton PTAC with 3.6 KWs of electric heat in the third floor equipment room Contractor must provide unit with the features, characteristics, and options shown in the air conditioner schedule; or approved equal.

E. Installation: Contractor must install all new units according to manufacturer’s installation instructions.

Provide and install compatible insulated wall sleeves according to manufacturer’s installation instructions.

The penetration must be caulked on all sides and be weather resistant.

F. PTAC unit on fourth floor equipment room is to remain as existing. Contractor must clean supply grille and replace the filter.

G. Contractor must demolish existing window unit on fourth floor, must dispose of equipment according to federal, state, and local codes. Existing NEMA receptacle and conductors are to remain. Contractor must patch wall opening with matching wall materials and finish. Contractor must provide coordination drawings of wall patch for approval prior to construction.

20. ELECTRIC UNIT HEATER

A. Demolish existing electric unit heaters in the first/ ground floor equipment room, first/ ground floor stairwell, and cab stairwell. The (2) existing units on the first floor are ceiling mounted, and the existing unit in cab stairwell is wall mounted. Demolish unit, thermostat, and control wires between thermostat and unit; the power conductors and all conduits can be reused.

B. Contractor must provide and install 3 KW EUH in first/ ground floor equipment room. Contractor must provide unit with the features, characteristics, and options shown in the electric unit heater schedule; or approved equal.

C. Contractor must provide and install 5 KW EUH in first/ ground floor stairwell. Contractor must provide unit with the features, characteristics, and options shown in the electric unit heater schedule; or approved equal.

D. Contractor must provide and install 10 KW EUH in cab stairwell. Contractor must provide unit with the features, characteristics, and options shown in the electric unit heater schedule; or approved equal.

21. ROOF AND EXTERIOR CAB

A. Existing. The existing ATCT roof assembly is a Sika Sarnafil G410 adhered system over ½” dens deck, 3” ISO, and vapor barrier over a structurally sloped steel deck. There are sarnatred sand coated walkway pads adhered throughout the perimeter of the cab roof. The existing Base Building roof is a Thermoplastic Polyolefin (TPO) membrane. Wet insulation on Base Building must be replaced as shown in attached ProScan Report and drawing LWM-21005021-D001.

B. Contractor to apply manufacturer instructed number of coats of elastomeric roof coating or approved equivalent. Coating will be applied to flat roof, roof side walls, HVAC curb flashing, and roof hatch flashing according to manufacturer’s installation instructions. Work to include substrate preparation and sealing air leakage/ water intrusion pathways. Contractor to obtain manufacturer’s 20 year roof warranty.

1. Clean and prep ATCT and Base Building roof deck. Prime entire roof deck and flashings with Sika EP Primer or equal. After curing, apply Sika Roof Pro 641 resin basecoat or equal over roof and all flashings. Install Reemat fiberglass reinforcement set in a wet coat of Sika Roof Pro 641 resin base coat or equal and let cure. Apply Sika Roof Pro 641 or equal resin topcoat to the entire roof and flashings and let cure. Apply a third coat of SikaRoof Pro 641 resin for traffic surfacing spreading quartz aggregate over entire roof.

2. Once new HVAC system is replaced, the elastomeric coating be applied to the flash the new unit and produce a seamless, watertight roof system. Apply elastomeric coating to the vertical surfaces of the roof hatch. Work includes substrate preparation and sealing air leakage/ water intrusion pathways. Application must follow all of manufacturer’s installation instruction. Match the color of the new elastomeric coating to the existing roofing material.

3. Use same roofing system over upper parapet roof wall and down the façade of the control tower, continue on, and the lower parapet roof wall. During the application process, carefully remove and re-install the lightning protection system to the catwalk.

4. There are areas that will require grinding away rust to prepare metal for adhesion to a sound substrate.

This would include railings on catwalk and cab roof, siding, and other areas where the liquid membrane will be applied. Replace existing caulk joints with Sikaflex 1A sealant or equal. Prime all steel with Sika EP Primer or equal and let cure. Apply Sika 641 resin base coat or equal. Install Reemat Premium set in a wet base coat of Sika Roof Pro 641 resin base coat or equal and let cure. Apply Sika Roof Pro 641 Resin topcoat or equal.

5. Use same roofing system under the steel catwalk on the failing EPDM roof system. Repair voids, tears, open seams, and prep EPDM roofing at tower shaft corners. Clean membrane per manufacturer’s recommendations. Apply EPDM Primer and let cure. Apply Sika Roof Pro 641 Resin base coat, set in Sika Fleece 140 in wet base coat. Apply Sika Roof Pro 641 Topcoat or equal. This work may require removing and reinstalling catwalk grating and exterior cab wall panels as needed.

C. Products. Contractor to must submit all products for approval.

D. Attached will be the infrared roof moisture survey from Proscan.

END OF SECTION

APPENDIX

Photo 1: Existing York roof top 8.5 ton package unit label

Photo 2: Image of the field installed electric heat accessory

Photo 3: Electric heat label

Photo 4 and 5: side views of existing HVAC unit

Photo 6: Top view of base building roof taken from ATCT roof

Photo 7: Photo of the equipment on the cab roof railing, and inner vertical wall.

INFRARED ROOF MOISTURE SURVEY

LAWRENCE MUNICIPAL AIRPORT

North Andover, MA

Prepared for:

Federal Aviation Administration

Date of Survey: April 11, 2023

109R Main St. Suite 9 P.O. BOX 513 AMESBURY, MA 01913

(978) 388-5155 Email: Proscan@Comcast.net

CONTENTS

Introduction

Purpose & Scope of Work

Equipment/Procedure

Environmental

Summary of Results

Roof Diagram with Infrared Images

I. Introduction Non-Invasive Roof Moisture Surveys

Because of the many potential problems associated with entrapped moisture, good roofing practice requires that wet roof materials, when found, be removed and replaced with new dry materials.

Periodic roof moisture surveys are a good way to detect moisture damage in the roof components and to find small problems that can be repaired before they involve large areas of the roof, potentially adding years to the serviceable life of the roof system.

Two non-invasive procedures are available for detecting areas of moisture damage in almost any type of flat roof. These procedures utilize infrared thermal imaging cameras and nuclear moisture/density gauges to detect moisture beneath the surface of the roof, particularly in the insulation layer beneath the membrane. Used separately or together, infrared and nuclear surveys are fast and cost-effective means of developing a detailed and accurate moisture profile of the roof.

Entrapped moisture may be detected by analyzing roof surface temperature patterns with an infrared camera at night. During the day, the roof absorbs heat energy from sunlight, passing a portion of this energy into the insulation beneath the membrane. As the sun sets and the roof begins to cool, dry insulation, which consists mostly of air, cools relatively quickly while wet insulation stays warm later into the evening. Heat stored by the wet insulation is conducted to the roof’s surface, creating warm areas that can be detected with an infrared camera.

Not all warm areas on the roof are caused by moisture. Heat discharged by mechanical equipment, variations in interior temperature and differential exposure to sunlight may cause temperature differences unrelated to moisture. As part of a properly conducted moisture survey, a nuclear moisture/density gauge is used to conduct further testing in such areas. The nuclear gauge operates by emitting a signal from a low-level radioactive source that reacts to the presence of moisture without piercing the roof. As the nuclear gauge does not rely on temperature variations to detect moisture, it is also used to cross check results obtained with the infrared camera, thus limiting the number of invasive test cuts required to confirm our results and reducing the likelihood of false positives. Nuclear gauge testing is also the only viable method of moisture testing stone ballasted membrane roofs.

In the final stage of the roof moisture survey, confirmed wet areas are outlined on the roof with marking paint, measured, photographed and plotted on a computer-generated diagram of the roof.

The information presented in this report is intended to help establish an appropriate roofing application, and may serve as the basis for bid comparison for any needed moisture related replacement work.

II. Purpose and Scope of Work:

In response to a request by the Federal Aviation Administration, Proscan technicians conducted an infrared roof moisture survey of the lower roofs at the Lawrence Municipal Airport control tower located at 492 Sutton Street in North Andover, MA. The purpose of the survey was to detect the locations and extent of moisture damage to the insulation or other components of the roof assembly beneath the membrane using non-invasive test methods.

Moisture entrapped within the roofing materials may lead to one or more of the following problems:

Structural degradation of the roof and other building components Increased weight load to the roof structure Increased energy losses Mold and insect infestation Interior damage due to roof leaks Reduced serviceable life of the roof

Wet roof materials identified by our survey should therefore be removed and replaced with new dry materials in conjunction with roof maintenance, repair or replacement.

Our survey was conducted during evening hours on April 11, 2023, and included two lower roof sections of the control tower building. The upper tower roof was not scanned. Total roof area scanned was approximately 954 square feet of PVC or TPO membrane roofing on two levels.

III. Equipment & Procedure

Equipment used for the survey consisted of a FLIR Model PM360 High Resolution Thermal

Imaging Camera operating in the short-wave spectrum (best for roof testing), sensitive to a temperature differential of 0.1° F. The infrared camera was used to scan all roof areas to detect thermal anomalies potentially indicating the presence of sub-surface moisture.

Where the infrared camera indicated the presence of moisture, the location was marked on the roof, measured, photographed and plotted on a roof diagram. All areas of the roof were scanned at least twice.

To the extent possible, our scanning and reporting procedures are conducted in accordance with

ASTM C1153-10-R2015 (Standard Practice for Location of Wet Insulation in Roofing Systems

Using Infrared Imaging).

IV. Environment:

The following information is provided in compliance with the Standard referenced above.

Weather conditions for the infrared scan were favorable, with daytime high temperature at 57° F and clear sky. Nighttime low temperature during the time of the survey was 48° F with clear sky and wind at 10-15 mph. There was no precipitation during the 24-hour period preceding the survey, nor were there any areas of standing water, debris, or other objects limiting access to any roof area.

V. Summary of Results:

The results of our survey are shown in detail on the roof diagram and accompanying charts in the next section of this report.

The following is a summary of our findings:

Our survey detected thermal anomalies indicating the presence of sub-surface moisture at three locations, affecting a total combined area of 101 square feet, or about 10.5 percent of the total roof area scanned. Two of the areas were found on the larger roof section, while one is located on the small connector roof between the building sections.

A small membrane puncture was noted in the wet area on the connector roof, a likely cause of moisture at that location. No obvious physical defects were noted within the areas on the larger roof. The location of the puncture is circled with spray paint, shown in Photo #3 accompanying the roof diagram.

All wet areas are marked on the roof membrane with weather resistant oragne spray paint.

No cores samples, moisture probes or other invasive procedures were conducted by our technicians. Our results were sufficiently clear to preclude the need for cutting or otherwise compromising the membrane.

The above figures represent the actual dimensions of the wet areas as they are marked on the roof and shown on the diagram. For replacement purposes, each area should be expanded slightly beyond its spray-painted boundaries in order to include any moisture migration that may occur prior to replacement, and simplified in shape where needed. The final moisture-related replacement figure will therefore be somewhat larger than noted above, typically by 10-25 percent for most roofs.

For future reference, it should be noted that roof leaks may occur as a result of many different causes, including membrane defects such as small tears or punctures, improper sealing of equipment penetrations and defective equipment or wall flashings. Unless these defects cause the insulation layer or other materials under the membrane to become wet, it is unlikely that infrared or nuclear surveys will be useful in resolving leaks. This report is intended to provide information as to the current locations and extent of moisture damaged materials. While locating wet material often helps to resolve leaks, infrared and nuclear surveys are not guaranteed to determine the source or cause of any roof leak.

Once moisture penetration of the roof components occurs, it is likely to spread. Infrared and nuclear surveys are effective means of identifying small moisture problems before they involve large areas of the roof, resulting in potential moisture damage and costly replacement.

Consideration should be given to performing moisture surveys on a regular basis, typically every three years during the warranty period and every year thereafter in order to extend the potential serviceable life of the roof.