Attachment B VHA Directive 1810 Appendix D.pdf

February 16, 2021 VHA DIRECTIVE 1061(2)

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APPENDIX D

PREVENTION OF LEGIONELLA DISEASE FROM COOLING TOWERS AT

DEPARTMENT OF VETERANS AFFAIRS MEDICAL FACILITIES

1. BACKGROUND

Non-potable water is water that is not of drinking quality but may be used for other purposes. Examples of systems that use non-potable water include cooling towers, which present a particular risk for Legionella exposure because they can provide an environment for growth of Legionella and subsequent transmission via water vapor or droplets emitted from the systems. Cooling towers have been identified as a source for outbreaks of Legionella disease (LD), which have included numerous cases identified over a short period of time. Conditions such as humidity, wind velocity and other factors can influence the travel distance of the contaminated aerosols. Since the aerosols generated by cooling towers can travel some distance, some LD cases have been reported to occur several miles away from the source. Legionella growth in cooling towers can be controlled through prevention and mitigation methods. These practices are critical to mitigate frequent and extended exposure of large numbers of people to Legionella-contaminated aerosols. This appendix delineates requirements for addressing the risk of Legionella growth in, or transmission from, cooling tower systems.

2. REQUIREMENT

Each Department of Veterans Affairs (VA) medical facility that owns and operates one or more cooling tower systems must ensure that a Cooling Tower Policy and Cooling Tower Management Plan is developed for the systems and that it remains current at all times.

3. VA MEDICAL FACILITY POLICY AND PLAN FOR MANAGEMENT OF COOLING

TOWER SYSTEMS

The Cooling Tower Policy must be reviewed and updated whenever there are additions, significant changes or, at least every 5 years. The Cooling Tower Management Plan must be reviewed, certified and updated annually at a minimum. The Cooling Tower Management Plan must include the following:

a. Cooling Tower Inventory. Document the location of every cooling tower system at the VA medical facility. Identify the technical details of the cooling tower(s), including the manufacturer and model, size and date of manufacture.

b. Systems Risk Analysis. At a minimum, for each cooling tower on the campus, the Cooling Tower Management Plan must address the following critical risks that can directly or indirectly impact Legionella growth or transmission.

APPENDIX D

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(1) System Design and Operation.

(a) The design of the system must undergo a documented risk analysis to ensure that the performance criteria are met and that the design addresses the risks discussed below.

(b) Siting and access of a cooling tower/cooling tower system must be reviewed for impact of drift and water vapor discharge relative to Heating, Ventilating and Air Conditioning (HVAC) air intakes, door and window openings, as well as the common path of travel and congregation of patients, staff and visitors. Additionally, the impacts of structures and other equipment on the operation of the equipment and systems must be reviewed.

(c) The sequence of operation must be reviewed to verify that the equipment can be operated as designed and that the operation addresses the risks discussed below. The review must be documented.

(d) There must be a current system schematic with detail on the system interconnection, equipment and instruments complete with a written sequence of operation for the system and the chemical treatment systems.

(2) Flow Analysis.

(a) The system must be reviewed for proper circulation in all branches of the non-potable system and in the presence of dead-end piping and stagnant areas.

(b) This review must include an understanding of operation, and address stagnation and low flow as a result of operation of system valves and controls. The review must be documented.

(3) Biological/organic Material.

(a) The presence of biofilm, algae and protozoa in a non-potable water system will be accelerated by the presence of required nutrients, such as organic material, and optimal growth conditions, such as warm water. The VA medical facility must establish a plan to minimize these conditions, or the effect of the conditions, and ensure optimal system control.

(b) The exposure of the water in a cooling tower system to direct sunlight also may accelerate biological growth and fouling.

(4) Poor Water Quality.

(a) Since the cooling tower inherently removes contaminants from the air that passes through it, organic and inorganic material near the tower must be controlled to mitigate contamination of the tower should these substances become airborne. An evaluation of these issues must be conducted to develop a plan to minimize their impact.

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(b) The Municipal water supply quality must be verified in order to ensure the chemical treatment regime provides the desired cooling tower water quality, and optimize blowdown, makeup and treatment options.

(5) Cooling Tower Equipment. Refer to VHA Engineering Standard ES-2019-001 for information and requirements related to the equipment and its maintenance and operations located at:http://vaww.hefp.va.gov/resources/water-safety-management-legionella-vavha-policies-guidance-supplements. NOTE: This is an internal VA website that is not available to the public.

c. System Operational Requirements and Procedures. There must be a current written operating plan for each system. The plan must include:

(1) System schematic with all equipment and instrumentation uniquely labeled (tag number) including chemical treatment. All equipment, valves and instruments must be physically labeled to match the schematic.

(2) Detailed sequence of operation for all modes of operation to include chemical treatment system. Sequence of operation must reference and be correlated with the schematic. Requirements for the sequence of operation, monitoring, operation and maintenance of the cooling tower and systems is defined in VHA Engineering Standard

ES-2019-001.

(3) Process to address any deficiencies or concerns raised in a report from any person related to the control measures being inadequate or requiring improvement.

d. System Maintenance Requirements, Frequencies and Procedures. There must be a current written maintenance plan for each piece of equipment and system that complies with the requirements of this directive, VHA engineering standards and the manufacturer’s recommendations and industry standards. The details of the requirements for the plan, inspections and reporting intervals are defined in VHA Engineering Standard ES-2019-001.

e. Procedures/Plans for Emergency Action Related to Biological Exceedances.

There must be a current written Emergency Action Plan for each system that complies with the requirements of this directive, VHA engineering standards, the manufacturer’s recommendations and industry standards. The plan must include:

(1) Procedures to address positive biological findings during testing.

(2) Standard operating procedures for remediation of equipment in addition to procedure for operating the system equipment during remediation process.

(3) Process to confirm if remediation was successful and if not, what further action is to be taken.

(4) Required personal protective equipment (PPE) during remediation.

(5) Required material, equipment and supplies to properly remediate.

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(6) Details on what the intended outcome is, as well as a method of documentation and evaluation.

(7) Process to address any deficiencies or concerns raised in a report from any person related to the remediation process.

f. Water Chemistry and Biological Testing Requirements, Frequencies and Procedures. There must be a current written Testing Plan for each system. The plan must include the following at a minimum:

(1) A list of all systems with testing frequency, thresholds and requirements. All systems must be tested as defined in this directive or per the manufacturer’s requirement, whichever is more stringent, including frequency.

(2) Written standard testing procedures for each system, including specific procedures for:

(a) Process to obtain sample, standard sample size and chain of custody process.

(b) Required PPE.

(c) Required material, tools and supplies to complete the work properly.

(3) Water Chemistry Testing Requirements.

(a) Water chemistry must be continuously monitored for biocide, corrosion control, pH, conductivity and turbidity. Water temperature also must be continuously monitored.

(b) Data on the water quality must be collected on the water chemistry hourly and upon alarms.

(c) Biocide and corrosion control additions must be automated and based on monitoring input.

(d) Water chemistry must be manually tested each month to confirm and recalibrate the accuracy of the continuous monitoring systems.

(4) Written biological testing procedures and frequencies using the requirements listed in paragraph 4 of this appendix.

(5) Process to address any deficiencies or concerns raised in a report from any person related to the testing process.

g. Data Evaluation and Record Keeping Requirements and Procedures. There must be current written records and an Evaluation Plan for each system. The plan must include:

(1) A process that defines the data to be collected and the form it must be in. At a minimum, the following must be addressed for each cooling tower/system:

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(a) Maintenance and inspection data on the cooling tower and systems;

(b) Water chemistry testing and monitoring data and deviations;

(c) Chemical treatment data, changes to rates of injection and data on why rates were modified;

(d) Environmental testing data and water chemistry and temperature of tests; and

(e) Remediation and supplemental action data.

(2) The method used to evaluate the data and any actions that need to be taken relative to any deviation or trends associated with the data;

(3) Identifying responsible persons for each process; and

(4) A method for filing, data retention and data retrieval.

4. BIOLOGICAL TESTING PROTOCOL AND INTERPRETATION OF RESULTS

This section provides overarching requirements for testing cooling towers for bacteria and describes actions to be taken.

a. Legionella Validation Testing. Sampling of each cooling tower for Legionella by culture methodology must be performed within 7 days of startup and every 90 days during periods when the cooling tower is operational or operational-ready (i.e., cleaned, disinfected, full of water and ready for operation). For routine water testing, collection of swab samples is not required, although a VA medical facility may choose to collect swab samples in addition to water samples. Swab samples alone do not meet the requirement of this directive.

(1) Sample Number and Locations. The number of water samples is dependent on the size and configuration of the cooling tower. At a minimum, samples must be collected from each basin/sump, and the supply to and return from the chiller(s). If the chillers are on a common header, only one sample is required. NOTE: Depending on the time of the year and VA medical facility location, a VA medical facility may have some cooling towers that are operational and some that are not. These testing requirements only apply to those cooling towers that are operational or operational-ready.

(2) Additional Sample Information. At the time that cooling tower water samples are collected for Legionella detection, also collect the following information for each sample: pH, biocide level and temperature.

(3) Laboratory Requirements. Once collected, samples are to be processed for Legionella detection by a testing laboratory with proficiency in microbial testing of cooling tower water. NOTE: Refer to Appendix C, paragraph 2.b. for requirements for choosing a laboratory for Legionella testing.

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(4) Testing Modality. All cooling tower water samples must be analyzed using a Legionella culture method. Use of additional Legionella detection methods (e.g., PCR) is a local decision; however, the use of PCR to screen for Legionella-negative samples (“PCR negative screen”) to then decide which samples must then be cultured is not permitted.

(5) Interpretation of Legionella Culture Results from Water Testing and Mitigation Actions. Below are the minimum action levels and requirements in response to cooling tower Legionella culture results.

(a) Sample is <10 colony forming units per milliliter (CFU/ml) - No action required, Maintain Cooling Tower Management Plan

(b) Sample is l - Review system operations including chemical treatment system. Perform immediate Remediation for cooling towers (see note below, paragraph 4.a.(5)(d)1.). Retest the cooling tower 3-7 days after completion of Remediation. <1000 CFU/ml, repeat Remediation for cooling tower (at increased concentrations) and retest at same interval until <10 CFU/ml is attained. see paragraph 4.a.(5)(c). Review Cooling Tower Management Plan and update as necessary (e.g., using information from assessment of system operations, Legionella positivity results and response efforts).

(c) Sample is - Review system operations including chemical treatment system. Perform immediate Disinfection for cooling tower (see note below, paragraph 4.a.(5)(d)2.). Retest the cooling tower 3-7 days after Disinfection. If retest is for cooling tower and retest at same interval until <10 CFU/ml is attained. Immediately perform Disinfection for cooling tower at an increased concentration/duration AND retest and repeat actions until <10 CFU/ml is attained. Review Cooling Tower Management Plan and update as necessary (e.g., using information from assessment of system operations, Legionella positivity results and response efforts).

(d) Notes.

1. Remediation for cooling towers. Treat the cooling tower water system with either a different biocide or a similar biocide at an increased concentration than what is currently used. Treatment must be maintained for a minimum of 2 hours, or longer if required to ensure the chemical is circulated throughout the system fully.

2. Disinfection for cooling towers. Dose cooling tower water system with a minimum of 10 mg/L of free residual halogen and dispersant for at least eight hours. Then the system is drained and flushed with clean water and the wetted surfaces are cleaned (cooling tower sump, fill, drift eliminators, etc.). Following this, the system is refilled, dosed to 1 to 5 mg/L of free residual halogen and circulated for 30 minutes, then drained. Finally, the system is refilled, routine treatment is re-established, and retesting is done for verification of treatment.

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3. Please refer to the following pH ranges for the selected halogen. For chlorine treatment, the pH should be 7.0 – 7.6; and for bromine treatment, the pH should be 7.0

– 8.7. For higher pH values treatment times may need to be extended.

4. Stabilized halogen products should not be used for remediation or disinfection.

(6) Documenting Testing Results. Documentation is required for environmental Legionella testing (e.g., date, location and results), any assessments of positive results, any remedial action taken and efficacy of remedial actions. A report of these items is to be submitted to the Facility Water Safety Committee, Facility Safety and Health Leadership Committee and Infection Control Committee.

(7) Reporting Environmental Testing Results. VA medical facilities are required to report environmental testing results, taken in accordance with Legionella testing requirements in this directive, to the VHA Water Safety Management Tool (WSMT) database or equivalent. NOTE: This requirement pertains to reporting of samples taken specifically for Legionella testing, including related readings such as pH, biocide level and water temperature. It does not pertain to reporting of routine or continual engineering control monitoring; these results should be recorded locally to monitor implementation of controls.

(a) The required content, frequency and timeframe for reporting results to the WSMT must be in accordance with the database User Manual. NOTE: The current WSMT User Manual can be found at the VHA Water Safety Management & Legionella Resources intranet site at: http://vaww.hefp.va.gov/healthcare-engineering/water-safety-management-legionella. This is an internal VA website that is not available to the public.

(b) Reporting of environmental Legionella testing results from cooling towers is required for samples taken for any component of this directive, such as routine testing, post-remediation testing or investigation of a LD case or cases. NOTE: VA medical facilities are required to report and verify the number of cooling towers that are operational and operational ready in the WSMT or equivalent on a quarterly basis in accordance with the User Manual.

b. Total Aerobic Bacteria. Total aerobic bacteria testing can provide information on whether engineering controls are preventing bacterial growth. Total aerobic bacteria testing is to be performed at system start up and every two weeks while the cooling tower is in use. Information regarding total aerobic bacteria testing requirements and interpretation of results can be found in VHA Engineering Standard ES-2019-001.

NOTE: While total aerobic bacteria testing (of which heterotrophic plate counts, or HPC, is one example) can provide information about general water quality in the cooling towers, there is no reliable correlation between total aerobic bacteria and Legionella values. The HPC testing requirement is included in this document as a reminder and is additional to the Legionella testing described here.