Public comments for: Cooling Towers - New Chapter 8 in Title 24 of the Rules of the City of New York to establish rules for maintenance of cooling towers

Comments

Comment:
The following comments are submitted on behalf of Consolidated Edison Company of NY, Inc. (“Con Edison”): Con Edison owns and operates cooling towers that are part of the critical utility infrastructure. These units include providing cooling for underground power feeders and chilling for liquid natural gas storage. The continuous operation of these units is critical for reliable utility service. As such, Con Edison performs regular maintenance and water quality of testing of these units. These units are currently registered with NYC and NY State. (1) Proposed Section 8-04 requires a weekly visual inspection of all wetted surface within the cooling tower. Con Edison operates a process cooling tower at its liquid natural gas (LNG) plant used for the chilling of liquid natural gas from April through November. Con Edison also operates cooling towers used for the cooling of underground electrical feeder cables. These units cannot be shut down for a weekly inspection without negatively impacting utility system reliability. A partial visual inspection can be performed by opening access doors, but not all areas within the towers are visible from the access doors. We request consideration in the regulation for critical utility infrastructure cooling towers that cannot be shut down on a routine basis.
Agency: DOHMH
Comment:
Towers used by Dry Cleaners are significantly smaller than cooling towers used on large buildings. In addition, Dry Cleaners are small businesses where the owner does all the maintenance, etc. Some of the revised Rule 8 is beyond the ability and resources of the small tower owner. The attached comments attempt to provide a version for small tower owners that they can comply with, one that also accomplishes the goal of eliminating the spread of Legionella.
Agency: DOHMH
Comment:
Bill Pearson, CWT See attached PDF for comment.
Supporting Document:
Agency: DOHMH
Comment:
Please see attached .
Supporting Document:
Agency: DOHMH
Comment:
Please see the attached comment letter and supporting documentation from Natural Systems Utilities. The purpose of this letter is to respond to Section 8-05(e): Make-up water and provide information about on-site water reclamation facilities and the use of reclaimed water within evaporative cooling towers. Our extensive testing indicates that these water reclamation facilities provide superior pathogen protection for cooling towers due to their on-site disinfection and continuous monitoring and that these water reclamation facilities should be encouraged as sources of supply for cooling tower make-up water.
Agency: DOHMH
Comment:
Here are my 2nd and 3rd comments. 2. Sections 8-04 (a) and 8-05 (f) (1) conflict. The first says “weekly” and the latter says “daily”. If a cooling system is equipped with a conductivity monitor (as most all are), weekly testing is adequate. Also, the “water Quality Parameters” listed at the end of Section 8-02 are examples and much more extensive than needed. For example, conductivity is an indirect measurement of total dissolved solids (TDS). Depending upon the type of water, TDS may be about 80% of the conductivity. Unfortunately, TDS tests require the expense of laboratory analysis and a week or longer to get the test result. Temperature and pH will not vary for a given system. The water treatment professional anticipates and considers fluctuations when designing the treatment program. ORP is not needed unless the water treater is utilizing ORP to control the halogen biocide feed. Test procedures do not exist for many biocide chemistries. The water treatment service company will test many other chemistry parameters monthly or quarterly to best understand the treatment program for corrosion and scale control. Weekly bacteriological indicator tests using dip slides should be adequate to estimate microbial content (as stated in Section 8-05 (f) (2)), but please do not incorporate this type of data in your Table 1. 3. Section 8-05 (e) Makeup Water includes the statement …”must install a drift eliminator”…. I cannot envision how a drift eliminator would be installed or needed in a reclaim water tank being used for tower makeup. Your Section 8-04 (e) already requires drift eliminators in the cooling towers. Why mention it in Section 8-05 (e)?
Agency: DOHMH
Comment:
This is first of three comments. Ladies and Gentlemen, January 3, 2016 I offer the following comments relative to your November 20th notice proposing a new Chapter 8 (Cooling Towers) to Title 24 of the Rules of the City of New York. Your document for Maintenance of Cooling Towers appears to be well written and contains a great deal of useful information for Building Owners and Operators to consider and act upon. I do, however, believe that a few items need to be clarified and some sections deleted. You need to avoid the appearance of micro-managing and rely on the experience and qualifications of water treatment professionals. I offer the following. 1. The 1st, 3rd and 4th columns of Table 1 on pages 13 and 14 are quite similar to Appendix 4-A in the recent New York State Legionella regulations and the Legionella “Cooling Tower Control Strategy” guidelines as published by The Special Pathogens Laboratory (SPL). However, neither the NY State nor the SPL documents contain the bacteria testing data you show in your 2nd column. If fact, I have never seen such a comparison by anyone else. Please acknowledge your data source and validity for such data comparisons. All data I have seen shows very poor correlation between your Column 2 bacteria tests and Column 3 Legionella results. Also, on-site bacteria dip slides and laboratory HPC test results typically do not produce comparable test results with themselves or with Legionella. Bacteria dip slide manufacturers may use different formulations for their dip slide agar. Standard Methods for laboratory HPC tests can utilize different agars. Some tests may produce results in 2 days such as typical with dip slides whereas laboratory HPC tests may require 2 days or 5 to 7 days depending upon the agar used and testing objectives. In comparison to dip slides, laboratory HPC procedures can measure a wider range of bacteria types and can include biocide stressed organisms that can be cultured during the 5-7 day procedure. I recommend you consider deleting the 2nd column and let the water treatment professionals decide what bacteria tests they want to utilize to evaluate the effectiveness of their water treatment programs to best comply with your requirements for quarterly testing of Legionella.
Agency: DOHMH
Comment:
This question is about the section in the proposed rules and regulations to exclude side stream filtration. To single out and exclude side stream filtration has no benefit and actually hinders the ability to increase safety. Side stream filtration allows for increased redundancy which actually decrease chances of fatalities exponentially. This is bc all fatalities from legionella came from human error in form or another. This could mean the correct chemical was not present, the chemical could have been diluted, staffing could have been on vacation and someone not as proficient was in charge. There also could have been a build up of scaling and bio - film that was present and created a habit for bacteria to lay dominant until the right conditions were present to multiply. Side stream filtration might not need to be a mandatory solution, however this engineered solution to add to the safety of an overall system should not be excluded. Many best practices in collaborative reports that have been done as recent as 2014 by RAND organization with CDC, ASHRAE, and Cooling tower institute sight side stream filtration and associated forms of bacteria control as a best practice. Side stream filtration also allows for water conservation and energy measures. This is a global concern but even more of a concern in NYC where the aqueduct will be shut reducing almost half of the in coming water supply into NYC. In most commercial buildings cooling tower make up water can be responsible for as much as 50 percent.
Agency: DOHMH
Comment:
See the attached document from REBNY and BOMA/NY.
Agency: DOHMH
Comment:
Part III References: 1. The use of Copper-Silver Ionization - Title 40 Code of Federal Regulations - US EPA Safe Water Drinking Act 2. CDC Updated Guideline and Best Practices for the Control of Legionella by Rand Corporation for Western 3. Pennsylvania, Oct 2014, Executive Summary, page X 4. ASHRAE/ANSI Standard 188-2015 Section 7 5. Cooling Tower Institute (CTI) Guideline: Best Practices for Control of Legionella, July 2008, Section IX 6. Legionella Exposure Control Plan, Sept 2013, Ohio state University EHS/OSIH Section 4.1 7. Dept of Energy, for Energy Consumption using Biofouling Thickness Chart and Savings calculation with the increase efficiency of heat transfer equipment. It is worthy to note that these references cited the alternative use of Copper-Silver Ionization, UV Lights, Electro-Magnetic Frequency devices, Ozonation with side-stream filtration. As a brief education on cooling towers: In a building envelope, the majority of cooling water passes through an open circuit cooling tower where used cooling water undergoes a thermal reduction of 10 degrees or more. A Cooling Tower operates like a wet scrubber that draws surrounding air that mixes with hot process water. It is through the contact of atmospheric air and cascading water inside the cooling tower that brings down airborne particles and waterborne debris, including dissolved solids to the water basin or sump. Because of inadequacies of water treatment in the majority of these buildings, the following hazards occur: • Incorrect water chemical balance • Buildup of scales and/or corrosion • Water stagnation, which breeds bacteria • Heat transfer becomes ineffective causing electrical draw to increase, thus decreasing efficiency • Clogged fills or tubes cause more water vapors drifting - more aerosols that may have bacteria that could affect air quality • Dilution of highly concentrated solubilized chemically-treated water leads to higher water usage by increase in bleed off and make up water Submitted by: Green Crown Water Systems, LLC Fluidyne
Agency: DOHMH

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