This is a service / maintenance or supply contract in Mesa, Arizona. Contact the soliciting agency for additional information.

Contractor shall supply Monthly Water Treatment services at all City buildings that are equipped with Chillers and/or Boiler. a. Design. All cooling water treatment programs shall be designed and certified by an Association of Water Technologies (AWT) "Certified Water Technologist" (CWT) to meet the following listed performance criteria. A listing of certified individuals is found on the AWT web site . Please do not submit an offer if your program has not been designed by a CWT; provide copy of designers CWT certificate with offer. b. Acceptable cooling water treatment program. Contractors shall have been engaged primarily in the business of water management for a minimum period of five (5) years. c. Corrosion Monitoring. Steel, copper, and brass corrosion coupons shall be supplied, removed, and analyzed by the supplier on a ninety (90) day cycle on all systems equipped with corrosion coupon racks so as to document control of corrosion. d. Corrosion Control. The cooling water treatment program shall control cooling system metals of construction to the following ninety (90) day exposure maximum corrosion rate values as measured in mils/yr. using NACE corrosion coupons of the designated alloy. Pitting corrosion, if present, shall be controlled to a rate no more than twice the listed rate values. Preference shall be given to Contractors that will warranty a lower corrosion rate. Please state expected or warranted maximum corrosion rates. System Metal UNS Number Material Maximum Corrosion Rate - mils/yr. aluminum A93003 Al3003 2.0 brass, cartridge C26000 CDA 260 0.5 carbon steel G11000 C1010 2.0 copper C11000 CDA 110 0.2 zinc - zinc 5.0 The cooling water treatment program contractor shall be capable of providing corrosion coupon racks, coupon holders, and corrosion coupons fabricated of the above alloys; and laboratory evaluation of exposed corrosion coupons according to NACE procedures, in order to confirm compliance with the above specifications. For offer costing, Contractor will utilize four place corrosion coupon racks - one for each Cooling System (both closed and open loops). Chemical products supplied shall prevent "dezincification" of any brass components present in the cooling system. Contractors must specify the methodology used with their treatment program to control "white rust". Chemical products supplied shall control the formation of "white rust", deposition of zinc carbonate resultant from rapid corrosion of galvanized components, to the maximum extent possible if an alkaline chemical treatment program is used. The preferred method of control shall be use of specific chemical corrosion inhibitors, which are incorporated into the supplied products. Control via lowered cycle operation is an acceptable method for compliance but is discouraged due to water conservation considerations. Use of pH adjustment by acid addition as a method of white rust control is discouraged due to the major control, maintenance, and health/safety problems presented by feed of acid. Contractor shall note specific method utilized to control white rust in their program. e. Scale control. Chemical products supplied shall prevent formation of scales containing calcium, magnesium, silica, barium, and/or iron on heat exchange surfaces at the recommended cycles of concentration. Please state exact generic scale control chemistry used for program offered. Scale formation may be evaluated by examination of heat exchanger surfaces; pipe spools in hot water returns; installation of scale coupons in high temperature sections of the system; digital heat transfer test units (Example: Advantage Controls Model ADPM-1A); conductivity, calcium hardness, and alkalinity cycles of concentration comparison; and mass balance studies on the cooling system. The program supplier shall have the in-house, or contract, laboratory capacity to undertake mass balance studies using atomic absorption spectrophotometer analysis of the water samples. Contractor shall confirm the specific laboratory to be utilized, in-house or contract, and if an AAS or ICAP is available. Provide copy of laboratory certification by state or ISO. The supplier shall, as part of routine service calls, evaluate conductivity, calcium hardness, and alkalinity cycles of concentration by comparison to ascertain if the cooling system is experiencing scaling. Additionally, supplier shall perform periodic calculations of Langelier Saturation Index or Ryznar Index and report no less than quarterly to client.