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1.4 General
.1 Duct sizes on drawings indicate clear inside dimensions. For acoustically lined or internally insulated ducts, maintain inside duct dimensions.
.2 Where duct sizes are shown in nominal metric sizes, round and oval duct sizes may be supplied in the nearest available sizes in equivalent imperial units.
.3 Proper sized openings shall be arranged for in the correct locations through all slabs and walls. Openings shall be planned to include for the installation of fire dampers at all rated fire separations.
.4 Where ducts penetrate roofs, provide roof curbs with flashing and counterflashing.
.5 Arrange for 100 mm [4"] high by 100 mm [4"] wide concrete curbs around all duct penetrations through floor slabs outside of duct shafts.
.6 The project drawings are diagrammatic and although efforts have been made to provide information regarding the number of offsets and transitions, not all are necessarily shown. Changes may be required in duct routings, elevation and duct shape to eliminate interference with structure and other services. All required adjustments shall be established when coordinating and field measuring the work prior to fabrication and must be provided as part of the contract and all associated costs must be considered and included.
.7 Ductwork used on this project shall be clean and free from scale, corrosion and deposits. All ductwork shall be degreased and wiped clean of all oil and other surface films with appropriate solvents prior to installation.
.8 All ductwork shall be delivered clean to the site and maintained in clean condition. Dirty ductwork shall be removed from site.
.9 Where welded ductwork is indicated, the welding shall be continuous with Everdur welding. Tack welding is unacceptable except as specifically noted. Paint damaged areas with zinc coating after welding.
.10 Provide seismic restraints for ductwork in accordance with SMACNA "Guidelines for seismic restraints of mechanical systems and plumbing piping systems".
3.8 Ductwork Leakage Test
.11 Leakage test all 750 Pa [3"] and greater static pressure supply ductwork installed under this contract, as recommended in the SMACNA H.V.A.C. Air Duct Leakage Test Manual, 1985 Standards, to a static pressure 500 Pa [2" W.G.] in excess of the specified ductwork design static pressure.
.12 Use equipment capable of demonstrating leakage.
.13 Test the first 30 m [100 ft] of installed ductwork in the presence of the Consultant.
.14 Test a 30m [100ft] section of 500 Pa [2"] static pressure ductwork, where complete systems over 30m [100 ft] long are installed under this contract to a static pressure of 500 Pa [2" W.G.].
.15 The total allowable leakage for the entire system shall be not greater than [5] percent of the total system capacity.
.16 Submit test reports for all ducts tested.
3.9 Ductwork and Plenum Cleaning
SPEC. NOTE: Use this item for low budget projects, where duct cleanliness is not critical.
.17 All ductwork and equipment installed shall be free of scale, debris and dirt.
.18 Maintain all duct and equipment openings covered with poly or equivalent to prevent the entry of dirt.
.19 Clean all plenums and buried supply ductwork with an industrial vacuum cleaner on completion of the duct and plenum installation.
.20 Install air filters of the specified performance.
.21 Blow out all supply ductwork, (by means of the supply fan) on completion of the duct and plenum installation and prior to installation of air terminals.
.22 Ductwork shall be considered clean when all foreign material visible to the naked eye has been removed. A random sampling review by the Consultant will be conducted to check for cleanliness.
3.10 Ductwork and Plenum Cleaning
.23 Responsibility
.1 This Contractor shall be responsible for and ensure that all ductwork, installed under this contract is internally CLEAN, when handed over to the Owner. This responsibility includes the entire systems, from outdoor air intakes to air terminals and from air terminals to relief outlets. It includes all ductwork, lined and unlined, all plenums and all equipment within or connected to ducts and plenums.
.2 The surfaces shall be considered clean when all foreign materials capable of particulating and visible to the naked eye are removed.
.24 Installation Procedure
.1 All ductwork shall be wiped clean prior to installation.
.2 LEED Requirement: Oil film on sheet metal shall be removed before shipment to Work Site. Ducts shall be inspected to confirm that no oil film is present.
.3 Close all dampers immediately following installation thus checking the operation and retarding movement of contaminants through the system.
.4 Seal all openings at the end of each day and at such other time as site conditions dictate.
.5 Floor openings to be capped with sheet metal or floor grilles plus 0.15 mm [6 mils] thick poly sheet.
.6 Other openings to be covered with 0.15 mm [6 mils] thick poly sheet taped so as to be air tight.
.25 Cleaning Procedure
.1 On completion of the duct and plenum installation and prior to the installation of air terminals and prior to balancing of the air systems, but not until the areas are substantially clean (floors have been swept and vacuumed) and all "dirty" construction has been completed, employ an approved Cleaning Agency to vacuum clean the following:
.1 All air handling units.
.2 All plenums.
.3 All supply and return air ducts.
.4 All exhaust air ducts.
.2 All components within each system shall be thoroughly cleaned and shall include but not be limited to the following: coils, fans and motors, silencers, air terminals and mixing boxes / air valves.
.3 When connecting to existing supply ductwork, clean existing supply ducts upstream from connection back to the filters. Clean existing supply ductwork downstream from new connections to outlets.
.4 Cleaning shall generally be by high capacity power vacuum. High-pressure compressed air, wire brushing and/or non-toxic solvent cleaning shall be used where dirt or scale cannot be removed otherwise. Coils shall be de-scaled.
.5 The Cleaning Contractor shall be responsible for removing and replacing filter media. This contractor will remove the temporary filters and replace with new after cleaning the systems.
.6 The Cleaning Contractor shall mark balancing damper positions before cleaning and return them to their original position when cleaning is completed unless the system is still to be balanced.
.7 Reinstall any grilles, registers and diffusers, which may have been removed for cleaning purposes.
.8 In accordance with CSA Standard Z317.2-01 – Clause 6.10.7.2, Class I air handling systems shall be cleaned and disinfected prior to occupancy.
.9 After the duct systems have been cleaned they should be resealed if they are not being used. Provide filter media on the return air terminals if the return air fans are run after cleaning has been completed.
.10 The Cleaning Agency shall perform a full inspection of the duct interior. Utilizing a fibre optic borescope with dedicated light source, inspect interior ductwork surfaces, and ductwork accessories including terminal units, mixing boxes / air valves, ductwork liners, duct-mounted coils, filters, dampers, humidifiers and all other appurtenances within the ductwork system.
.11 Spot checks will be made by the Consultant during the cleaning process to verify that the required standard is being met. When substantial performance is claimed, final spot checks will be made to verify that the ducts are clean. Make available for the use of the Consultant a fibre optic borescope with dedicated light source. If any ducts are found to be unclean, then they shall be recleaned.
.12 Ducts serving very clean areas served with 85% NBS or HEPA filters shall be reviewed by the Consultant utilizing the equivalent of a white glove wipe technique.
.13 Submit a report from the cleaning agency that certifies all specified air systems have been cleaned (complete Mechanical Form MF 171 in Section 15955).
3.11 Ductwork and Plenum Cleaning
.26 As a condition of acceptance all new air ductwork systems shall be clean. Systems shall be cleaned if examination indicates the need. The Contractor shall confirm system cleanliness in writing (Form MF-171) and shall assume responsibility for misinformation and correction of damage. Before starting fan systems, all supply outlets shall have clean cheesecloth attached to them.
.27 Final systems cleaning, if required, shall be performed by an approved Cleaning Agency.
.28 The cleaning shall be to the satisfaction of the Consultant and Owner.
End of Section
TAG technical services inc. Project No. XXX
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