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USGC Gulfstream Program Page 1 of 37The Dow Chemical Company

Texas Operations (TXO) Potable Water Requirements and Guidance Document

In this Document The following topics are discussed in this document:Note: Click on the HYPER L INK S below to go to the specific topic.

Section Contents Page

1.0 Introduction 2

2.0 Work Practices – General 4

3.0 Work Practices – Cross Connection Management and Control

16

4.0 Work Practices – Break Tank/Pressure Boosting Systems 25

5.0 Licensed Plumber Work Process 29

6.0 Maintenance Practices 31

7.0 Design and Equipment Specifications 34

8.0 Emergency Procedures and Protocols 40

Texas Operations (TXO) Potable Water Requirements and Guidance Document, Section 1: Introduction

Introduction The purpose of this document is to provide plant staff with additional information and tools to comply with both the T-12 Texas Operations Potable Water Standard and the revised T-15 Texas Operations Emergency Safety Shower and Eye Wash Stations Standard.

In this Section Following is a list of topics in this section:

Topic See Page

Overview 2Background 3Applicability 3Benefits of the Standard 3

Potable Water Requirements This is a controlled document. No un-authorized modifications.And Guidance Document Health, Safety, and Environmental

DOW CONFIDENTIAL – Do not share without permission



Overview The T-12 Potable Water Standard lists the following Guiding Principles for potable water use at Freeport Operations:

1. Environmental Operations (EO) will provide potable water to Freeport facilities (inside block limits, process units, and buildings) that is safe for consumption, is available at adequate flow and pressure for facility operations, and that meets Federal, state and local regulatory requirements.

2. Texas Operations (TXO) has adopted the 2003 International Plumbing Code (IPC) as its site plumbing ordinance, consistent with Dow’s engineering practices. Any installation, alteration, repair, replacement, or remodeling of potable water systems within TXO must comply with Texas Commission on Environmental Quality (TCEQ) and IPC requirements to ensure the safety of site personnel and to protect the plant / building potable water storage and distribution systems. In accordance with IPC 102.2, potable water systems in existence as of the date of this standard shall be allowed to remain in place unless the existing system has the potential to create an unsanitary or unsafe condition.

3. No water pump, pipe, or other equipment that has ever been used in non-potable water service will be used for potable water.

Potable water is intended for human consumption, hygiene, and safety shower use only and should not be used within a process area unless there is no viable alternative.

Back to Top Continued on next pageTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 1: Introduction, Continued

Background The T-12 Potable Water Standard establishes the requirements for Freeport Environmental Operations to comply with the following regulations and internal standards governing potable water systems:

LPP 7.9 Potable Water Systems (ODMS 06.03.B.35.03)

Title 30 Texas Administrative Code Chapter 290 (30 TAC §290), pertaining to public drinking water, as administered by the Texas Commission on Environmental Quality (TCEQ).

International Plumbing Code (2003).

Applicability The T-12 Potable Water Standard applies to all Texas Operations owned systems (including all categories of water wells). All exceptions MUST be approved by the Site Licensed Plumber, Regulatory SME, or Licensed Water Operator.





Benefits of the Standard

Protects the system from cross contamination Ensures that potable water pipeline work is performed under the supervision /

at the direction of a licensed plumber Provides for the disinfection of the Potable Water system, which protects

against bacterial growth Ensures the consistency and approval of materials used in Potable Water

service Merges all Federal / state rules, regulations and Dow Loss Prevention

Principles into one comprehensive site standard

Back to TopTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 2: Work Practices - General

Introduction This section further explains the procedures and general operational guidelines that are included in section V-VI of the T-12 Potable Water Standard.

In this Section The following is a list of commonly used Potable Water work practices. Each topic is addressed individually in the T-12 Potable Water Standard and is discussed more fully throughout the chapter.

Topic See Page

ProceduresUse of Licensed Plumber 5Exemptions for Routine Maintenance 6

General Operational Guidelines 7

Loss of Potable Water Pressure 7

Cleaning and Flushing of Potable Water System 8

Disinfection of Potable Water System 9

Water Filters 11

Water Softeners 12

Reuse of Equipment 13

Pipe Labeling 14

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PROCEDURESUse of Licensed Plumber

The following requirement governing the use of a Licensed Plumber for work on a facility potable water system is included in the T-12 Potable Water Standard:

Any installation, alteration, repair, replacement, or remodeling of the facility potable water system will be conducted through the Freeport Environmental Operations Licensed Plumber Program.

Background and Guidance:

A licensed plumber is an individual licensed by the Texas State Plumbing Board who is skilled in the planning and supervision of plumbing-related work, as well as the practical installation, repair, and service of plumbing. A licensed plumber is knowledgeable concerning plumbing codes, ordinances, or rules and regulations governing plumbing, who alone, or through individuals under his supervision, performs plumbing work, and who has successfully undergone examinations and satisfied the requirements of the Texas State Board of Plumbing Examiners. Section 5 further describes the Licensed Plumber Work Process.

The requirement to use a licensed plumber for work on the Freeport Operations potable water system is included in the T-12 Potable Water Standard to ensure that the right procedures and materials are used on the system. A common example is the use of polyvinyl chloride (PVC) pipe. PVC pipe in a hardware store is either stamped with “NSF-PW” or “NSF-DWV” (see photo at right). The “PW” designation means the pipe is approved for use in potable water systems. The “DWV” designation means the pipe is approved for only drain, waste, and vent applications. This concept applies to all piping and fixture materials throughout the facility. A licensed plumber or water operator has the training to select the proper materials. Section 7 includes additional details on the Design and Equipment Specifications which must be followed.


In some cases, after repairs, the potable water system must be disinfected with chlorine and sampled for bacteriological contaminants. A licensed plumber or water operator has the training to know when and how to disinfect the potable water system and collect any required samples following completion of the repairs.





PROCEDURESExemptions for Routine Maintenance

The T-12 Potable Water Standard includes an exemption for routine maintenance activities that can be performed by facility staff (as opposed to requiring use of the Licensed Plumber):

Exemptions for Routine Maintenance: The routine maintenance activities listed below may be performed by facility staff without being coordinated through the Freeport Environmental Operations Licensed Plumber Program.

1. Replacement, repair, or maintenance of existing plumbing fixtures, including hot water heaters.

2. Adjustments to closed loop systems.3. Replacement, repair, or maintenance of in-line potable water filters.4. Replacement, repair, or maintenance of an entire safety shower assembly or

any pieces of the assembly.5. Installation of atmospheric vacuum breaker (AVB) backflow prevention

assemblies or an air gap on a flexible hose.6. External clamping of a leaking potable water pipeline.

Background and Guidance:Certain routine activities, as listed above, can be performed by maintenance or other plant staff and do not have to be coordinated through the Licensed Plumber Program. These activities do not involve alterations to the potable water system. Disinfection and sampling of the water system is not required when the above tasks are performed.

These exemptions for routine maintenance are included in the T-12 Potable Water Standard to give facility staff flexibility in terms of completing routine repair and maintenance tasks on plant / building potable water systems.


General Operational Guidelines

The sections below describe the General Operational Guidelines included in Section VI of the T-12 Potable Water Standard. Additional procedural details are provided in the T-12 Procedures document.





Loss of Potable Water Pressure

The following are the requirements for Loss of Potable Water Pressure, as included in the T-12 Potable Water Standard:

1. In the event of a loss of potable water pressure where the integrity of water in the piping system is maintained, the piping system shall be flushed for at least fifteen minutes.

2. In the event of an extended outage (>72 hours) of the potable water system (or if there is any reason to believe that contamination has occurred) the Licensed Plumber shall be contacted to facilitate flushing and bacteriological testing.

Background and Guidance:The state of Texas and Dow Texas Operations requires a minimum pressure of 35 psi (minimum 20 psi during fire fighting emergencies) within the potable water distribution system. When the pressure drops below 20 psi, this can allow backsiphonage of water along with any potential contaminants into the potable water system.Maintaining the integrity of water in the piping system generally refers to a situation where water pressure is lost, but the piping remains intact and sealed (that is, the line is not opened up). Simply closing the valve that supplies potable water to your block is one such example. Although pressure is lost, the interior of the piping has not been exposed to any non-potable water source or other external source of pollutants, thus the potential for contamination is minimal. If the potential for contamination exists, however, the system should be flushed for at least fifteen minutes before continuing to use the system.


An extended outage refers to loss of line or system pressure over a period of time sufficient to potentially allow biological growth within the line / system, even if the line / system has not been opened to the outside environment. For the purposes of this discussion, an extended outage is one which lasts longer than 72 hours. Another example of an extended outage would be an extended shut-down in preparation for a hurricane. If the potable water system is out of service for a prolonged period of time you should contact the Licensed Plumber to arrange for disinfection and testing of the system before placing it back in service.

Finally, if the physical integrity of the potable water distribution system is breached and the possibility exists of contaminants being introduced into the system, the Licensed Plumber should be contacted for guidance. An example of such an event would be the accidental rupture of an underground potable water line by a backhoe during trenching activities. If contamination is suspected for any reason, it is best to contact a Licensed Plumber to properly disinfect the system.





Cleaning and Flushing of Potable Water System

This section provides guidance on best practices for the cleaning of potable water lines before placement into service. The key point of this best practice is to make a distinction between “cleaning” and “disinfection” of the line. As discussed below in the General Operational Guidelines – Disinfection of Potable Water System, lines must be disinfected before being placed into service.However, an equally important but often overlooked step consists of cleaning the lines prior to disinfection. This step is important regardless of whether the task is completed under the Licensed Plumber Program or involves routine maintenance completed by plant employees. Similar to the best practice with respect to cutting oils discussed in Section 6, potable water lines or equipment must be cleaned of foreign matter that could obstruct or contaminate the potable water distribution system. This must be done prior to placing the line in service or having the line disinfected (if required). Examples of foreign matter include sediment, welding slag, rags, and even hand tools.


The first step to ensure that no foreign matter is introduced into the potable water system is to carefully inspect the work area prior to joining pipe or installing equipment to ensure that all tools, hardware, containers, rags / wipers, and other small objects are accounted for. For other solid/liquid contaminants, the best practice for cleaning lines / equipment to remove these materials consists of 1) flushing water from a low point or 2) installation of a blow-off valve to flush the line. Similar to the flushing requirement following a loss of potable water pressure, 15 minutes of flushing at full flow / pressure will typically be sufficient to clean the line.

In summary, a line that is not cleaned of foreign matter is not ready to be disinfected. Only after the line has been cleaned and any foreign matter removed is it ready for disinfection and placement into service.





Disinfection of Potable Water System

The following are the requirements for Disinfection of Potable Water Systems, as included in the T-12 Potable Water Standard:

The Licensed Plumber will follow Potable Water Disinfection Piping Specification G4S-0240-01. The line must be disinfected and tested before the water is used for consumption. The disinfection process recommended for the particular application will be reviewed and implemented, followed by bacteriological sampling to ensure the potable water in the line is free of harmful bacteria prior to placing the line into service.

Background and Guidance:As described in Section 610 of the International Plumbing Code, new or repaired potable water systems shall be purged of harmful materials and disinfected prior to use. The Licensed Plumber shall perform or oversee the line disinfection.All sampling will be conducted by a Licensed Plumber. The Colloidal Bacteria test (also referred to as a Bac-T test) takes at least 24 hours to perform. If the potable water system must be returned to service quickly due to safety concerns (e.g., an immediate need for safety showers / eye wash stations), then potable water service may be restored after first communicating to the plant that 1) the water has NOT been confirmed to be safe and 2) consumption should be avoided until results are obtained. Note: In an actual emergency, restore potable water service immediately—safety trumps health!






If necessary, a Licensed Plumber contractor shall collect bacteriological samples prior to releasing the system for potable water use. Samples shall be collected using the procedures described in the document entitled, “Coliform Sampling for Public Water Systems” (TCEQ RG-421, January 2005). The Licensed Plumber contractor shall deliver the bacteriological samples to a TCEQ-certified laboratory for analysis of total coliform presence or absence using an approved laboratory method. The data from the lab will be reported directly to the Licensed Plumber contractor and the contractor shall review the data and determine whether to place the potable water system back in service.30TAC §290.42(j) requires that all chemicals used in drinking water systems conform to ANSI/NSF Standard 60. The TCEQ website specifies that the bleach container used for disinfection must contain a label that specifies that the product “meets NSF Standard 60” or has the NSF symbol. If neither marking is on the container, the manufacturer must be contacted to confirm whether the bleach is manufactured to the NSF standard. The following bleach included in the MSMS ordering system has been confirmed to meet the standard:

MSMS# 38036, Pure Bright Germicidal BrandNote that requirements for disinfection, inspection, and testing of potable water lines before placement back into service are found in the state drinking water regulations (30 TAC §290) and are also included in LPP 7.9 Operational Mandatory Requirement 3 (OM3).An important consideration for disinfection of lines and equipment is discharge of the chlorinated water used for disinfection. This disinfection water may contain free chlorine levels of 300 to 500 mg/L. For comparison, these levels are approximately 1000 times greater than free chlorine levels in potable water. Discharge of chlorinated water used for disinfection shall be performed in accordance with the Potable Water Disinfection Piping Specification G4S-0240-01 and the T-12 Potable Water Procedures.






The first option for discharge of the chlorinated water is discharge to the plant process sewer. Depending upon your facility or process unit, you may need to coordinate with Unit Operations to ensure that the discharge of this superchlorinated water does not adversely react with other wastes present in the process sewer. In addition, if the discharge is greater than 500 gallons, you must contact the Environmental Operations Control Room at X 2269 at least one hour prior to the discharge to inform them that this discharge will be arriving at the Wastewater Treatment Plant. Regardless of the quantity (number of gallons) discharged, the total discharge of superchlorinated water must be tracked using a Waste Profile Number (WPN).Note that discharge of the superchlorinated water to your facility surface drainage system (through storm water drains or ditches) is NOT an acceptable disposal option. If the superchlorinated water cannot be discharged to the process sewer, you must coordinate with the Licensed Plumber to arrange for collection and transport of the superchlorinated water directly to the Wastewater Treatment Plant.

Water Filters The following requirements pertain to point-of-use water filters as described in the T-12 Potable Water Standard:

It is permissible for all potable water in point-of-use service (such as drinking fountains, water taps, ice machines and coffee makers) to have an in-line filter installed prior to the point of use. Filter installation and replacement should be coordinated through Managed Services. The filter cartridge should have the date of the last filter replacement marked on the filter housing and the filter should be replaced at least twice per year.

Background and Guidance:Water treatment facilities ensure proper treatment of potable water to ensure its safety; however, water filters are recommended at the point-of-use to remove unwanted sediment or naturally-occurring organic contaminants and improve taste, aesthetics, and odor. It is important to mark the date on the filter housing to ensure replacement at regularly scheduled intervals and to prevent fouling of water filters.




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Water Softeners The requirements specified in the T-12 Potable Water Standard for point-of-use water filters are also applicable to water softeners installed at individual service locations. The following guidelines should be observed:

Softener installation and replacement should be coordinated through Managed Services. The softener cartridge should have the date of the last filter replacement marked on the softener housing and should be replaced at least twice per year.

For single point-of-use applications, i.e. where potable water is intended for human consumption, an in-line check valve is acceptable for use as backflow protection. Contact the Licensed Plumber at X 9484 for a recommendation on the type and size of check valve to install prior to your water softening system.

For any commercial-type water softener, i.e. a water softening system connected to process water, a reverse pressure zone (RPZ) backflow preventer should be installed. Such applications are regarded as high potential health hazards and must have appropriate backflow protection in place.


Background and Guidance:Depending upon your physical location or the process within your plant/block, you may have either a commercial- scale water softening system installed or a much smaller undersink-type system. In both cases, cartridges or tanks containing ion exchange resins are used to remove unwanted “hardness” (calcium and magnesium ions) from the water, which improves water quality and reduces the build-up of scale on plumbing fixtures, boilers, or other process equipment. Such systems may also be used in advance of other treatment steps to produce demineralized water for use in laboratory applications. Because of the potential for biological growth to occur, and due to the health hazard posed by process water connections, appropriate backflow protection must be installed. In addition, although larger units often regenerate based on an automatic timed cycle, smaller units must be changed out/serviced at regular intervals as with point-of-use water filters.



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Reuse of Equipment

The following requirements govern the reuse of equipment according to the T-12 Potable Water Standard:

Piping and equipment that has been used for any purpose other than conveying or storing potable water shall not be used in the potable water system.

Background and Guidance: Both Texas regulations and the International Plumbing Code include requirements that equipment used for potable water cannot have been used for any other service other than for potable water. When pipe or equipment is used for some other service (such as conveying oil, glycol, benzene, etc.), the equipment may continue to leach low levels of contaminants even after thorough cleaning. Further, the previous service may have caused corrosion or pitting of the equipment that impacts its ability to safely convey potable water. For these reasons, the practice of re-using equipment for potable water service previously employed in some other service is prohibited.This policy impacts Dow by not allowing materials previously in service as process piping, or if the previous use of the equipment is unknown, from being placed in potable water service. If you are aware of any circumstances within your facility where non-potable water or process chemical equipment has been re-used for potable water service, this equipment must be replaced.






Pipe Labeling The following T-12 Potable Water Standard requirements apply to the identification and labeling of potable water lines:

1. All potable water service connections in areas that can be readily recognized as supplying potable water (such as kitchens, restrooms, and drinking fountains) do NOT need to be labeled. All other potable water service connections must be positively identified using a sign or label that reads “POTABLE WATER”. Potable water lines entering a building as well as those that may be accessible inside a building shall be properly labeled in the same manner on each side of the wall where entry is made. Facility valves on potable water lines shall be clearly labeled for ready access. Only potable water may be labeled as POTABLE WATER.

2. Existing pipes outside of buildings shall be labeled at a minimum interval of 200 feet and at each point where the pipe passes through a wall, floor, or roof. New pipes shall be labeled in accordance with Potable Water Piping Systems Design Requirements G4R-6800-01 which requires a minimum interval of 50 feet. For new and existing buildings where potable water piping is exposed, interior pipes shall be labeled at a maximum interval of 25 feet, per IPC 608.8.1.

Background and Guidance:All piping used for potable water distribution must be properly labeled to clearly differentiate potable water from non-potable water. The label must have white block lettering against a green background as in the following example: POTABLE WATER. The label should be legible when read by a person standing on the ground (see photograph at right for additional examples).

All piping inside existing buildings that is not exposed (i.e. within walls, ceilings, and attics) is NOT required to be labeled. Existing buildings will be “grandfathered”, as the above standard applies only to new buildings.


Exposed piping within buildings shall be labeled at minimum 25 foot intervals. This will apply in shops and warehouses where potable water piping is typically exposed.

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Texas Operations (TXO) Potable Water Requirements and Guidance Document, Section 3: Work Practices – Cross Connection Management and Control

Introduction This section addresses in more detail the cross connection control requirements of Section VIII of the T-12 Potable Water Standard.


Topic See Page

Cross Connection Control – General Requirements 17Potential Cross Connections & Prevention 19

Types of Backflow Prevention Assemblies 20

Approved Backflow Prevention Assembly Options 21

Installation and Registration of a Cross Connection Device 24

Cross Connection Training 24

References 24

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Cross Connection Control – General Requirements

The following are the requirements for Cross Connection Control, as included in the T-12 Potable Water Standard:

1. Each plant/building within a site will provide an approved, reduced pressure zone assembly (RPZ) or an air gap at the block limit to prevent backflow from the block into the potable water distribution system and potential adverse impacts to other users. Note: the word ‘approved’ refers to the devices or systems designated by TCEQ for use in this service.

2. Within ISBL, potable water cannot be connected to any condensing, cooling, or industrial process or any other system of nonpotable usage unless it is protected from potential cross connections by an air gap or the appropriate backflow prevention assembly. This prevents any backflow from an industrial process into the potable water of the block.

The facility potable water system must be inspected annually to ensure there are no potential or physical cross connections with any other utilities or processes (e.g., pumps, seals, vessels, or sewers). For additional details review the remainder of this document.

Background and Guidance:A cross connection is defined as a point where equipment or piping is directly or indirectly connected to a potable water system with the potential to allow contaminants to enter the drinking water system. When a cross connection occurs, contaminants may enter the system through either back-siphonage or backpressure and eventually become distributed throughout the potable water distribution system. Back-siphonage is the reversal of normal flow in a system caused by negative pressure (vacuum or partial vacuum) in the supply piping. Backpressure is the reversal of normal flow in a system due to an increase in the downstream pressure above that of the supply pressure. Continuous pressure is a term applied to an installation in which the pressure is being supplied continuously to a backflow preventer for periods of over 12 hours at a time.






The terms “health” and “non-health” hazard are used to describe the degree of hazard posed by a potential cross connection. Health hazard cross connections have the potential to create a danger to the health of potable water users, causing illness, injury or death, if a hazardous substance or contaminants are introduced into the water supply. Health hazards are considered to be chemicals with an NFPA Health rating of 1 or greater, or an NFPA Flammability rating of 3 or greater. A guide to the NFPA rating system is available for review. In addition, a list of NFPA ratings for chemicals and products manufactured by Dow has been compiled. A non-health hazard cross connection has the potential to introduce substances into the water supply that are a nuisance or are aesthetically objectionable, but which will likely not harm the health of potable water users.Control of cross connections is important to prevent the contamination of potable water systems. Drinking water contamination is defined as any non-potable water or waste that interferes with the potable water distribution system. Not all contaminants are harmful, but those that are can consist of bacteria, metals, organic matter, or toxic chemicals. A person can be exposed to these substances by either consuming the water or through physical exposure. Therefore, it is essential that measures are taken to identify and control cross connections and so protect human health.






Potential Cross Connections & Prevention

Three types of cross connections are commonly found in water distribution systems: (1) potable water pipe / other pipe, (2) potable water pipe / equipment, and (3) hose connections. First, potable water pipe / other pipe is defined as a direct connection between the potable water piping and any other piping system which carries water from another source of lesser or unknown quality (i.e. a well, river water, or storm water runoff). Second, a potable water pipe / equipment cross-connection is defined as a direct connection between potable water piping and some type of process equipment, such as mix tanks or vats.

Finally, a hose connection exists where hoses are used to fill containers or maintain water levels. If hoses are left submerged in liquid containers and a drop in line pressure occurs, backsiphonage can cause contaminants within the container to enter the potable water system. Unlike the first two examples, hose connections represent an indirect connection between potable water and a system of unknown or lesser quality because they can be removed—they are often, though not always, only temporary.A Guide to Cross Connections has been developed which lists potential cross connections commonly found at Dow plants. This guide describes how each piece of equipment may be connected to the potable water system, the type of backflow prevention assembly required, and restrictions on installation, testing, and inspection of the backflow prevention assembly.






Types of Backflow Prevention Assemblies

Backflow prevention assemblies are grouped into four major device types (reduced pressure zone assembly, pressure vacuum breaker, atmospheric vacuum breaker, and air gap). Each device type is designed to be used in a particular type of application while providing a specific level of backflow protection as summarized in the table below. A description of the function of each device is located in the Guide to Cross Connection Control Devices.

Backflow Prevention Assembly

Type

Protects Against Can be used for health hazard

cross connection?

Can be used under

continuous pressure?Backpressure Backsiphonage

Reduced Pressure Zone

Assembly (RPZ)

Yes Yes Yes Yes

Pressure Vacuum

Breaker (PVB)Yes Yes No Yes

Atmospheric Vacuum

Breaker (AVB)No Yes No No

Air Gap (AG) Yes Yes Yes Yes

The table below summarizes the potential or actual cross connection situations and specifies which type of backflow prevention assembly is required by the TCEQ. The cross connections listed are a Dow specific subset of those listed in 30TAC290.47, Appendix I.






Approved Backflow Prevention Assembly Options

Description of Potential or Actual Cross Connection

(applies only to connections with potable water supply)

Approved Backflow Prevention Assembly

RPZ PVB AVB AG

Mandatory Air Gap (regardless of Hazardous or non-Hazardous service)

Connection to ANY other Utility, other than Potable Water

Connection to ANY Process Equipment

Tank vats or other vessels containing toxic substances

Degreasing equipment

Sewage pump

Sewage ejectors

Connection to sewer pipe

Cooling towers

Connection to salt/river water cooling systems

Notes: = Primary backflow assembly option (reference 30 TAC 290.47, Appendix I).● = Other approved backflow assembly.

NOTE: Multiple selections are listed as options – only one assembly is required.









RPZ PVB AVB AG

Autoclave

Fire-fighting system (toxic foam-based)

Lawn irrigation systems with chemical additives

Steam generators •

Lab and Health Apparatus Washing Equipment

• •

Plant Laboratory supply lines •

Lab bench equipment , including Aspirators and lab sinks

• •

Heating Equipment (e.g., boilers)











RPZ PVB AVB AG

Cooling equipment

Kitchen Equipment – Commercial

Post-mix carbonated beverage dispensing machines

•

Lawn irrigation systems without chemical additives

•

Flexible Shower Heads •

Potable Water Hose bibbs •

Safety shower tail hoses •



A Backflow Prevention Assembly Equipment List has been developed which specifies model numbers for Watts control backflow prevention devices for each potential cross connection scenario.


Installation and Registration of a Cross Connection Device

The Licensed Plumber Work Process Flow Diagram illustrates the sequence of activities involved whenever a request is made to modify the potable water system. The Licensed Plumber Initial Job Review Checklist includes the backflow prevention checklists which identifies the steps required to install and register a cross-connection device.

Cross Connection Training

The Guide to Cross Connections Training program provides additional information on cross connections.





References For further examples of cross-connections, reference Chapter 2 in the EPA Cross Connection Control Manual.

Dow’s Loss Prevention Principle for potable water, LPP 7.9, contains the corporate requirements for cross connection control.

Back to TopTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 4: Work Practices – Break Tank/Pressure Boosting Systems

Introduction This section further explains the requirements for potable water break tanks and pressure boosting systems which is included as Section IX of the T-12 Potable Water Standard.


Topic See Page

Potable Water Break Tank and Pressure Boosting System 25Guidance for Maintaining Chlorine Residual in Systems with Break Tanks or Recirculating Systems

26

What do I do if I have a problem with biological growth? 27

Requirements for Potable Water Tanks 28

Potable Water Break Tank and Pressure Boosting Systems

As described in the T-12 Potable Water Standard, facilities equipped with break tank / booster pump systems must ensure a continuous flow of fresh water within the system to prevent biological growth within the system. Facilities that use in-line pumps to boost potable water pressure must have an automatic pressure cut-off device or pressure sustaining valve installed to maintain a minimum of 20 psig at the suction side of the pump.

Back to Top Continued on next pageTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 4: Work Practices – Break Tank/Pressure Boosting Systems, Continued



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Guidance for Maintaining Chlorine Residual in Systems with Break Tanks or Recirculation Systems

Facilities that have a break tank and booster pump as part of their potable water system require special consideration to maintain adequate chlorine residual levels in the water. For facilities with these systems, the Facility Potable Water Contact has the additional responsibility to know and understand how these systems operate and must pay close attention to the potential for problems (such as biological growth).The Facility Potable Water Contact must be familiar with the following features of the Break Tank System at their plant / building:

Volume of Break Tank Orientation and Function of Break Tank Nozzles Capacity of Booster Pumps Potable Water Demands (daily average, maximum, minimum) Potable Water Distribution Piping Layout

Two primary factors contributing to biological growth within break tank systems are 1) inadequate mixing of water within the break tank and 2) “water age” within the break tank and distribution piping. These concepts are discussed in more detail below:

(1) Inadequate Mixing of Water in Break TankTo ensure uniform distribution of chlorinated water throughout the break tank, the water inlet from the plant potable water header and suction outlet to the booster pump should be located such that short-circuiting of inlet water is minimized. For example, a good example of nozzle placement would be an inlet nozzle located at the top of the tank with the booster pump nozzle at the bottom of the tank on the side opposite the inlet nozzle. Such an arrangement promotes circulation of water within the tank and ensures that thorough mixing takes place. This minimizes the potential for water to become stagnant and possibly allow biological growth within the tank.(2) Water Age

In general terms, water age refers to the number of days that have elapsed between the water entering the break tank and the water drawn at the tap. For example, if the average potable water demand of your plant is 500 gallons per day and your break tank has a volume of 1,000 gallons, the age of water drawn at a tap close to the booster pump can be estimated at two (2) days. The water “ages” more at distant points in the distribution system, i.e. points farthest away from the main potable water header.






What do I do if I have a problem with biological growth?

Problems with biological growth tend to occur when the water age within a facility potable water distribution system exceeds two to three days. Therefore, the first line of defense is a thorough understanding of your break tank / booster pump system.Symptoms of a biological growth problem include: (1) taste and odor complaints, (2) color changes, and (3) water temperature increases. If you suspect that you have problems with biological growth, the following options are available:

(1) Increase water useThis option is the easiest to implement; however, it may not be the most efficient. It involves increasing water demand by creating a continuous 3 gpm flow (commonly termed blowdown or wastage) of water from the system. This action will decrease the water age within the system by maintaining a steady flow of fresh water into the break tank. While simple to implement, this solution wastes treated potable water.(2) Re-evaluate Break Tank sizeA problem with biological growth may be indicative of a break tank that is too large. Was your break tank sized based on a projected water demand that is higher than actual demand? Have buildings or process areas been shut down recently that would result in a reduced potable water demand? If you suspect that your break tank is too large, you can contact Plant Engineering or Environmental Operations – Water Distribution for assistance. See contact information on Potable Water ISBL website. (3) Install secondary disinfectionA third option for managing problems associated with biological activity is to install a secondary disinfection system to control biological growth within your potable water system. Examples of disinfection technologies include chlorination, ozonation, and ultraviolet light, among others. The use of such technology may be mandatory, depending on the quality of the water supplied. According to the Safety Shower Design Aid, “in locations with poor water quality, a sterilization unit must be considered for the water supply. A Ultraviolet Light sterilizer shall be specified based on bacteria growth allowances per local requirements and samples made from the water supply source. Input from the local hygienist is recommended.”

Consult Environmental Operations – Water Distribution for guidance on equipment selection and cost, system sizing, and other specifications.




http://emetl.intranet.dow.com/scripts/SinglePracticeOptions.asp?PracNo=G4D-5400-02



Requirements for Potable Water Tanks

As required in the T-12 Potable Water Standard, the Facility Potable Water Contact is required to conduct annual inspections for the following items with respect to potable water break tanks:

Plants with atmospheric potable water tanks in their blocks must ensure that an air gap of at least two inches (2”) or two pipe diameters, whichever is greater, is in place from the maximum water level of the tank (overflow or flood-level rim) to the inlet water nozzle of the makeup water header to prevent backsiphonage.

The tank overflow pipe or drain line must not exit or terminate below grade. A gap of two inches (2”) or two pipe diameters, whichever is greater, must be maintained between the pipe exit and grade.

If the tank is in a diked area, the two inch (2”) or two pipe diameter separation distance must be measured from the plane of the diked wall, i.e. above the flood level rim of the dike.

All potable water storage tanks must be inspected annually to insure that:- Vents are in place and properly screened- Roof hatches are closed and locked- Flap valves and gaskets protect against insects, rodents, and other vermin- Interior and exterior coating systems provide protection- Tank(s) and piping don’t leak- Instrumentation and controls are working

All potable water pressure tanks must be inspected annually to insure that:

- Pressure release device and pressure gauge are working- Air-water ratio is being maintained- Exterior coating system provides adequate protection- Interior coating is intact- Tank remains watertight- Instrumentation and controls are working

Back to TopTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 5: Licensed Plumber Work Process

Introduction This section further describes the procedures for use of the licensed plumber in modifications to the potable water system as required by Section V of the T-12 Potable Water Standard.






Topic See Page

Work Process Overview 29Licensed Plumber Roles and Responsibilities 30Testing of Backflow Prevention Assemblies 30

Disinfection of Potable Water System 30

Work Process Overview

The Licensed Plumber Work Process is described in the flow chart provided. All Work Orders will be generated by Site Maintenance / Operations. No potable water work may be performed until an authorized work order is executed. The Licensed Plumber will review incoming work orders on their work order screen on at least a daily basis. Upon receipt of a work order, Licensed Plumber staff shall review the task and negotiate a level of effort and schedule to finalize the work order prior to beginning work. Attached is the Licensed Plumber Initial Job Review Checklist that can be used to assist in developing the scope of work for the Work Order.During review of a Work Order, the Licensed Plumber contractor shall identify whether additional staff resources are needed to complete the work as scheduled. If so, the contractor shall coordinate with the Contractor Leveraging Contact (CLC) for assignment of additional staff.Following bacterial testing, and at the conclusion of the scope of work for each Work Order, the Licensed Plumber shall sign off on the completed job by entering the job number from the bacteria testing lab on the comment section of the work order. He will then close out the Work Order.

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Licensed Plumber Roles and Responsibilities

The Licensed Plumber(s) are employees of a plumbing firm under contract to Dow Chemical – Texas Operations to perform / monitor the installation, alteration, repair, replacement, or remodeling of potable water systems as well as the inspection and testing of backflow prevention assemblies as authorized by individual work orders.The Licensed Plumber firm shall conduct potable water work at Texas Operations under the direction of a Master Plumber as defined in the Occupations Code, Title 8, Regulation of Environmental and Industrial Trades, Chapter 1301. Refer to the Texas State Board of Plumber Examiners (www.tsbpe.state.tx.us) for a list of Master Plumbers holding a valid license.Testing of backflow prevention assemblies shall be conducted by a Certified Backflow Prevention Assembly Tester who has been certified by the TCEQ (as defined in 30 TAC 30, Occupational Licenses and Registrations; Subchapter B) to test Backflow Prevention Assemblies. For Texas Operations, this function is performed by the designated Licensed Plumber.



http://www.tsbpe.state.tx.us/



Testing of Backflow Prevention Assemblies

Testing of backflow prevention assemblies shall be as requested by Work Order and shall be reported on Form 99. Procuring tags and tagging backflow prevention assemblies is the responsibility of the Potable Water Contact. A copy of the completed Form 99 shall be returned to the EH&S Delivery contact for the plant / building and the Potable Water Contact.


Following repairs or new construction, the potable water system must be disinfected as discussed in Section 2 prior to returning the system to service.

Back to TopTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 6: Maintenance Practices

Introduction This section describes several common maintenance practices including use of cutting oil, pipe cleaning, disinfection, and use of an incidental maintenance variance.


Topic See Page

Use of Cutting Oil for Cutting and Threading Pipe 31Pipe Cleaning and Flushing 33Disinfection of Potable Water System 33

Use of Cutting Oil for Cutting and Threading Pipe

This section provides guidance on the selection and use of cutting oil for threading, cutting, or grooving potable water pipe within a plant, building, or other facility. Threading, cutting, or grooving of pipe for most work on your potable water system will be performed under the direction of the Licensed Plumber. However, at times personnel within your facility may thread, cut, or groove pipe when performing routine maintenance activities that are exempt from the Licensed Plumber requirement.Cutting oil is required to both cool and lubricate the cutting and threading dies. However, this cutting oil must be cleaned and removed before the pipe is placed into potable water service. There are no commercially-available cutting oils that are approved to remain as a coating on the pipe when placed back into potable water service. Even if you use cutting oil that is considered safe for human consumption (such as vegetable oil), the presence of an oil / water mixture in the lines would constitute a nuisance to plant staff due to objectionable taste, odor, and appearance.

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Texas Operations (TXO) Potable Water Requirements and Guidance Document, Section 6: Maintenance Practices, Continued

Therefore, the best practice involves using a thread cutting oil that has the following properties:

Contains no chlorinated or halogenated solvents Contains no PCBs and/or heavy metals

An example of a thread cutting oil (Ridgid Thread Cutting Oil) certified to meet these requirements is shown in the photograph to the right.In addition to using a quality thread cutting oil that is free of harmful additives, the risk of oil contamination within a pipe may be minimized by setting the pipe-cutting machine at a slight incline (elevate end opposite the cutting / threading operation) such that any oil does not migrate down the length of the pipe. The objective is to minimize the surface area of the pipe exposed to the cutting oil.Cutting oils that meet the requirements above may be either mineral oil-based (not water soluble) or synthetic-based (water soluble). Some synthetic oils are also biodegradable in addition to being water soluble. Regardless of which type of oil is used, all traces of oil must be removed from the piping before the line may be disinfected and/or placed into service. If a mineral-oil based product is used, and the affected area is easily accessible, the pipe can be cleaned with a solution of water and household dishwashing detergent (the detergent will help dissolve the oil). The advantage of the synthetic cutting oil is that the oil can be cleaned from the pipe using water only.

The final point of the threading oil best practice is that chlorinated solvents, diesel, gasoline, or other similar hazardous materials CANNOT be used to remove oil from potable water pipe or equipment. Use of these chemicals would defeat the purpose of using a cutting oil that is free of these chemicals as listed above. Due to possible health hazards, such compounds should never be used for cleaning potable water systems or components.

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Pipe Cleaning and Flushing

Prior to disinfection of piping, the pipe must be cleaned and flushed as discussed in Section 2.






After the pipe has been cleaned and flushed, the system must be disinfected as described in Section 2.

Back to TopTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 7: Design and Equipment Specifications

Introduction This section provides guidance on the design and equipment specifications which must be followed on potable water systems.


Topic See Page

New Installation Requirements 35NSF Standards 36EMETL 37Pipe Specifications 38

LPP 38

Incidental Maintenance Variance 39

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New Installation Requirements

The following are the requirements for new installation of potable water system components, as specified in Section V of the T-12 Potable Water Standard:

1. New underground potable water pipelines shall be installed no closer than nine feet in all directions to wastewater collection facilities. Where the nine-foot separation distance cannot be achieved (e.g., due to crossing pipelines), additional criteria must be met. Contact the Licensed Plumber or Environmental Operations Water Distribution Contact for additional guidance.

2. New underground potable water pipelines and wastewater mains that run parallel shall be installed in separate trenches. Additional criteria apply in cases where a new underground potable water pipeline parallels an existing wastewater main within nine feet. Contact the Licensed Plumber or Environmental Operations Water Distribution Contact for additional guidance.

3. There can be no physical connection between a potable water line and a sewer line.

4. Potable Water Systems may not be directly connected to any other process or utility system without an air gap established and maintained at all times.

5. Pumps taking water from storage tanks must have a low water level cutoff device.

6. Booster pumps that take suction from the potable water distribution system must be equipped with automatic pressure cut-off devices that turn off the pump when the suction pressure is less than 20 psi.

7. The preferred method of pressure maintenance is to locate the booster pump downstream of a storage tank with an air gapped connection to the public water system's distribution lines.

8. For modifications to existing systems, contact the Licensed Plumber or Environmental Operations Water Distribution Contact.


Background and Guidance:New Installation Requirements are similar to maintenance standards for the same reasons. It is important to protect the potable water system to ensure drinking water is safe for human consumption and use and that it remains free from contamination.

New water pipelines are protected from sewer contamination in several ways. This is most commonly accomplished by placing sewer pipes and water lines at least nine feet apart to ensure adequate physical separation. This protects water lines from contamination during maintenance or accidents, and also helps to reduce the likelihood of unintentional cross-connections.





NSF Standards Texas Commission on Environmental Quality regulations, 30TAC290, require that materials of construction and treatment chemicals used in public drinking water systems conform to American National Standards Institute/National Sanitation Foundation (ANSI/NSF) standards. NSF/ANSI Standard 60: Drinking Water Treatment Chemicals – Health Effects and NSF/ANSI Standard 61: Drinking Water System Components – Health Effects are both American National Standards, which means that the NSF Standards and the processes used to develop them conform to ANSI’s requirements for voluntary consensus standards. The standards are copyrighted, but may be used by any organization or individual for the purpose of product/material evaluation, testing, and certification.

NSF/ANSI Standard 60, first adopted by the NSF Board of Trustees on October 7, 1988 covers corrosion and scale control chemicals; pH adjustment, softening, precipitation, and sequestering chemicals,; coagulation and flocculation chemicals; well-drilling products; disinfection and oxidation chemicals; and miscellaneous and specialty chemicals for treatment of drinking water. The standard addresses the health effects implications of treatment chemicals and related impurities. Both the treatment chemical and the related impurities are considered contaminants for evaluation purposes. The two principal questions addressed are:

1. Is the chemical safe at the maximum dose, and2. Are impurities below the maximum acceptable levels?






Reaction by-products such as the disinfection by-products of chlorine, ozone, hydrogen peroxide, or other chemicals are not covered by this scope of the standard.

NSF/ANSI Standard 61, also adopted on October 7, 1988, covers indirect additives products and materials, including process media, protective materials, joining and sealing materials, pipes and related products, mechanical devices, and mechanical plumbing devices (including faucets). In essence, every material from the well or water intakes through to the faucet are covered.

NSF/ANSI Standard 61 addresses crucial aspects of drinking water system components: whether contaminants that leach or migrate from the product/material into the drinking water are above acceptable levels in finished waters.

The standard also covers products, components, and materials. When a material is certified under Standard 61, its certification indicates use restrictions on parameters such as maximum use temperature or surface area to volume ratio when the material is used in a finished product. This option allows manufacturers using certified materials to bypass some or all chemical testing when seeking certification, and assures that finished products meet all requirements.

EMETL The Dow Chemical Company Electronic Most Effective Technology Library (EMETL) contains the required corporate engineering procedure G4R-6800-01, Potable Water Piping Systems – Design Requirements. The minimum requirements in this document must be followed in the design, installation, operation and maintenance practices for potable water piping systems.


Pipe Specifications Pipe Specification PU93 has been established for potable water systems in

Texas Operations. This specification requires the use of stainless steel piping to meet NSF requirements. Pipe specification PU88 is no longer acceptable for use in potable water systems since the galvanized carbon steel components do not meet NSF requirements. Use of a pipe specification other than PU93 requires approval as identified in the Incidental Maintenance Variance paragraph later in this section.





LPP The Dow Chemical Company Loss Prevention Principle LPP 7.9 addresses corporate requirements for potable water systems in order to prevent contamination or loss of integrity. LPP 7.9 contains facility design criteria which must be incorporated into construction of potable water systems. The corporate standard addresses backflow prevention, coordination of changes through site potable water personnel, maintaining up-to-date system drawings, and system labeling. In addition, the standard includes a general requirement that design and operation of the potable water system must comply with regulatory requirements which for systems in Texas refers to 30TAC290.


Incidental Maintenance Variance

Incidental maintenance on a system can be performed with “like for like materials” when suitable NSF 61 products are not available and there is clear reason to believe that the improved system will maintain or reduce potable water consumer risks. This is particularly pertinent to the use of galvanized carbon steel pipe for maintenance services. Use of galvanized carbon steel pipe in potable service shall be allowed but limited to small emergency maintenance activities only. Otherwise, 316L stainless pipe shall be used. Where NSF 61 approved galvanized components are available they shall be used. The Incidental Maintenance Variance will be reviewed and granted each year by the ORM potable water compliance focal point.

PU88: Water-Potable. This specification cannot be used in North America without approval from the Environmental (EN) Tech Center CPPS Focal Point. Water Assess PU88 CPPS is owned by the Environmental (EN) Tech Center. For questions with respect to these CPPSs, contact the Environmental (EN) Tech Center CPPS Focal Point. Note: NRES-066. This piping installation is restricted from use in new piping installations or for existing 0061 systems in North America due to NSF61 Compliance. Prior Approval must be obtained before using this piping specification for minor maintenance repairs. Use of this specification without prior approval of the licensed plumber or CPPS Environmental Focal Point will result in removal of installed pipe and replacement with compliant pipe materials.

Back to TopTexas Operations (TXO) Potable Water Requirements and Guidance Document, Section 8: Emergency Procedures and Protocols

Introduction This section further describes the emergency protection requirements of Section VII of the T-12 Potable Water Standard and provides guidance on the potable water information that should be included in the block’s unit emergency plan.





In this Section Following is a list of topics in this section:Topic See Page

Freeze Protection Protocol 40Block’s Unit Emergency Plan 42

Freeze Protection Protocol

The following are the requirements for Emergency Protection, as included in the T-12 Potable Water Standard:

1. Per the Site’s Emergency Rough Weather Plan, precautions should be taken to prevent damage to potable water piping when a freeze is expected. Piping can be drained using low point bleeds. Only breathing quality air shall be used if it is necessary to blow lines dry. Other materials (nitrogen, compressed air, etc.) shall not be introduced into potable water piping systems. Prior to bringing the line back in service, the piping system needs to be flushed with potable water for a minimum of fifteen minutes to ensure that fresh potable water with disinfectant residual is obtained at the point of outlet. If the outage is extended (> 72 hours), the Licensed Plumber shall be contacted to collect samples and perform bacteriological testing.

Procedures for Potable Water Systems due to lines being out of service:

EnvOps Disinfection PW Lines Out of Service More Than 72 Hours

EnvOps Re-Commissioning PW Lines Out of Service Less Than 72 Hours

EnvOps Re-Commissioning PW Lines Out of Service More Than 72 Hours

2. Because of the potential for contamination, potable water lines cannot be blown clear using plant nitrogen or plant instrument air.

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Background and Guidance:It is important to consider whether pipes are located in areas prone to freezing (exposed outdoor locations) and whether they are insulated. Adding insulation to particularly vulnerable pipes may prevent the need to drain them in advance of cold weather events. Other options for freeze protection include the installation of heat trace, as on potable water lines supplying safety showers/eye wash stations. Consult with the Licensed Plumber on which option best suits your particular needs.Gases other than breathing quality air cannot be used to blow water lines dry. Plant and instrument air, for example, have the potential to come in direct contact with chemical contaminants in process areas. The same is true for nitrogen, which is used as an inert “blanket” to pad flammable waste and chemical product containers during loading, transportation, and unloading operations. In all of the above cases, it is possible for contamination to be introduced into the drinking water system from gases that have been used for other applications. The best way to properly safeguard the integrity of the potable water system is by using only breathing quality air for blowing down potable water lines.

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Block’s Unit Emergency Plan

All of the below scenarios need to be addressed in the block’s unit emergency plan. For each scenario, post the “Do Not Drink” notice found in the T-12 Potable Water Procedure document at each faucet until this issue has been resolved. 1. Loss of potable water pressure

a. Look for leaksb. If no leaks are found, notify Environmental Operations at x2269.c. Follow the block’s T-12 Potable Water Procedures on how to place the

line back in service.2. Suspected contamination

a. Isolate the affected section of the lineb. Notify Environmental Operations at x2269.c. Determine the source of contamination.

3. Confirmed contaminationa. Isolate the affected section of the lineb. Notify Environmental Operations at x2269.c. Determine the source of contamination.d. Develop a plan to flush from the system and manage the water

environmentally correct.4. Policy / protocol for checking cross-connections in event of notification.

a. Reference the RPZ Block List maintained by the licensed plumber.b. Verify that all backflow protection is in place.c. Evaluate the system for any potential, new cross connections.d. Document, repair, and notify Environmental Operations of any findings

and actions.

Back to TopTexas Operations (TXO) Potable Water Requirements and Guidance Document

Review History The following information lists at least the last two reviews to this document, and all reviews that were done in the last 12 months.

Date Reviewed By Comments





Revision History The following information documents at least the last 3 changes to this document, with all the changes listed for the last 6 months.

Date Revised By Changes

02/15/08 Potable Water Team

Added the Incidental Maintenance Variance section on page 32.

02/10/10 S. Benavides Formatted document and added page numbers to Table of Content.

9/19/2011 L. Emswiler Update of document to clarify requirements including cross connection section, licensed plumber procedures, and pipe labeling. Add Design and Equipment Specification section.

9/27/2011 B. BrannanS. Hensley

Review of document Info Map

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