HSP Pool Operator Manual

Transcription

1 HSP Pool Operator Manual High Sierra Pools, Inc. High Sierra Pools Certified Pool & Spa Operator HSP CPO

2 Content 1. Introduction Aims and Objectives Staff and responsibilities Management structure Operating the pool environment The pool operator Mechanical Systems and Other Considerations Pumping and Recirculation Filter Room Circulation and Recirculation Equipment Pool Outlets... 8 Overflow Gutters and Skimmers... 8 Main Drain Outlets... 9 Pool Suction Cleaner Pool Inlets Strainers Pumps Surge Tank Piping Valves Flow Rate Indicator Flow Controllers Pressure and Vacuum Gauges Heater Chemical Treatment Equipment Filter Systems Filters and Filtration Filters Gravity Filters Pressure Filters Filtration Water Treatment ph Disinfection Chlorination Combined Chlorine Super Chlorination Chlorine Compounds Chlorine Gas (Cl2) Electrolytic Chlorine Generation Sodium Hypochlorite (NaOCl) Calcium Hypochlorite (Ca(OCl)2) Lithium Hypochlorite (LiOCl) Stabilized Chlorine (Chlorinated Isocyanurates) Non-Chlorine Sanitizers Bromine Iodine Ozone Silver Non-Halogen Oxidizers Additional Pool Chemicals Algaecides High Sierra Pools, Inc Page 2

3 Chelating Agents Cyanuric Acid Defoamers Degreasers Flocculants Water Chemistry Water Balance Corrosion Control Irritation Control Stain Control Water Clarity Under- and Over- saturation Total Alkalinity Water Hardness The Langelier Index Chemical Testing Sample Handling Types of Tests Pool Water Testing Bacteriological Testing Chlorine Tests OTO (orthotolidine) DPD (diethyl-p-phenylenediamine) DPD Test Procedure Cyanuric Acid Testing Hardness Testing Total Hardness Testing Calcium Hardness Testing for Copper and Iron Oxidation-Reduction Potential (ORP) ph Determination Total Alkalinity Testing Total Dissolved Solids (TDS) Testing Testing with Prepackaged Test Strips Testing Schedules Maintenance and Operation of Swimming Pools Routine Maintenance and Procedure Daily Opening Procedure Daily Closing Procedures Weekly Procedures Monitoring, Reporting, and Record Keeping Preventative Maintenance Seasonal Maintenance Facility Safety Water Safety Drowning Drowning prevention Drowning signals Making Swimming Safer Safety Requirements Wading Pools Entrapment The Virginia Graeme Baker Pool and Spa Safety Act High Sierra Pools, Inc Page 3

4 6.3. Safety Around Water Electrical Storms Chemical Safety & Storage Avoid mixing chemicals Protective Measures Access Fencing and Barriers Safety Covers Alarms High Sierra Pools, Inc Page 4

5 1. Introduction 1.1. Aims and Objectives A clear, safe, sparkling swimming pool is the right of every user. It should also be the objective of every manager. In practice, this is sometimes difficult to achieve. Changes to the water s physical, chemical and microbiological conditions occur constantly in a busy pool some in seconds; others in hours or days. Only a trained pool operator can identify and manage these changes. This Handbook recognizes the unique needs of Victorian pool operators and has considered the types of equipment and treatment used, the local regulatory environment and the experience and expertise of Aquatics and Recreation Victoria. It was prepared in association with a committee of industry professionals with backgrounds in pool management, water treatment, pool maintenance and service, pool user groups and public health. This Handbook offers practical advice on pool operation and water treatment issues, encouraging pool operators to: follow safe working procedures maintain plant and equipment to achieve the desired service life achieve regulatory compliance provide the best swimming or bathing experience possible for the pool user Staff and responsibilities There are many factors critical to pool water quality and these are described in more detail later. They fall into three groups: human contamination, environment and design, construction and operation. Human contamination Skin, throat and fecal bacteria, body oils, cosmetics, ammonia and nitrogenous matter from sweat, urine, dirt, food, saliva and open infections. Environment Physical and chemical composition of pool water, algae and fungi, gases formed from chemical reactions, air and water quality and pollution, humidity, sunlight, evaporation. Design, construction and operation Pool bathing load, turnover, dilution, hydraulics, construction materials, chemical conditioning, disinfectants, dosing control, flocculants, filtration, testing and interpretation. Given these factors any of which can affect bathing conditions and become a hazard to health a pool or spa requires proactive water quality management Management structure Staff needs vary with pool size The actual management structure will vary according to the type of facility. For example, a small hydrotherapy, community or hotel pool will require a small number of multi-skilled staff. A large community swimming pool complex will require a team of specialized staff. All staff require training Whatever its size, maintaining the pool requires that all staff be trained to understand and interpret pool operations and water conditions. Personnel should be trained in plant operation and water treatment measures required to maintain water quality. Where possible, a manager or other person responsible for water quality should be professionally qualified High Sierra Pools, Inc Page 5

6 As the size and complexity of the pool increases, specialist staff are required. In a large multi-facility site, the services of qualified staff for day-to-day plant operations are indispensable. Their actions should be guided by documented plant operation manuals and maintenance inspection schedules. Peripheral staff are also important Understanding the pool water treatment process should not stop with the appointment of management staff. The actions of lifeguards and supervisors also have an effect on pool water quality. Relevant staff should have an appropriate understanding of basic water chemistry and the testing, water treatment, plant operation and the general procedures required to maintain good quality water. As well as supervision, lifeguards may be required to conduct accurate water tests, provide a hygienic pool area, ensure pre-swim hygiene and respond to a soiling incident. The supervisor should be sufficiently familiar with water quality to be able to correct a condition that could lead to water quality deterioration. If the pool water begins to lose clarity or fall below the relevant standards, the on-site supervisor must be able to decide if bathing should cease. Management responsibility Managers responsible for large, multi-purpose facilities may delegate day-to-day pool operation to team members with appropriate skills. Nevertheless, the manager still carries the ultimate responsibility. Whether or not the managers have hands-on skills, they must have a sound understanding of pool operations and be able to spot problems and institute remedies. For instance, a swimming pool with poorly maintained water is a perfect breeding ground for disease. Even a well maintained pool can provide a vehicle of transmission to patrons. Also, careless management of flocculants, filtration, disinfection and chemical balances can cause turbidity (cloudiness) that obscures swimmers and lifeguards vision of the pool floor, even in shallow water Operating the pool environment Cost Constraints With increasing demands on public and private expenditure, competitive tendering of public services and greater awareness of water and energy conservation issues, there is pressure to find more cost-effective ways to operate swimming pools. Water, energy, water treatment and waste water disposal costs are very real concerns for managers; but where the consequences of alterations and adaptations to limit these costs are not fully understood, disaster can follow. Poor training and techniques can increase costs In terms of capital expenditure, energy, maintenance and day-to-day operation, a swimming pool is an expensive item. Managers and staff should be trained to obtain maximum life from their facilities and to operate them cost-effectively. Lack of training and knowledge about energy conservation and water treatment systems can actually increase the cost of operations dramatically. Poor use of chemicals and methods may mean that major items of plant, equipment and buildings require early replacement. This can even lead to the closure of the facility. Poor maintenance and operation can often be attributed to a lack of professional expertise or knowledge (or possibly resources). Either way, it represents a failure of management, and may require the owners of pools, local authorities, schools or private operators to spend large amounts of money on pool refurbishment, sometimes within ten years of operation. This may include new filters, plumbing, pumps, tiling, grouting, clarifiers, steelwork in the pool hall, heating and ventilation plant, lighting and electrical work High Sierra Pools, Inc Page 6

7 The pool operator A pool operator should be appointed at each facility. This person should take responsibility for the overall operation pool plant and equipment and ensure that appropriate operational and maintenance activities are carried out. The pool operator must have a comprehensive knowledge of relevant statutes, regulations, codes and other standards. In pools that are open for long hours each week, responsibility for the daily operation of the plant may be shared. The pool operator should ensure that those left in charge have a working knowledge of the Regulations and can ensure that the treatment plant continues to provide pool water that meets these requirements. They should also be able to identify problems and know how to obtain corrective advice. Additional training may be required, to ensure adequate understanding of the statutory requirements. 2. Mechanical Systems and Other Considerations 2.1. Pumping and Recirculation The vast majority of today s pools and spas use closed systems. Cleaning (filtering) and treating the water requires recirculation to ensure that the entire pool contents are uniform. For best results, the water should exit the pool both at the surface and at the deepest point. The bottom drain removes fine solids, such as sand hair, and lint. The overflows skim off surface debris. When the pool is at rest (very few swimmers), the circulation system should draw about 80% of the recirculation from the surface and 20% from the bottom drain to ensure good cleaning and mixing throughout the pool. When there are many swimmers, their activities will create wave action that will increase the effectiveness of the overflow skimming action. At such time, the amount of re-circulating water drawn from the bottom drain can be increased to maintain good distribution throughout the pool and to remove bottom debris more quickly. How much recirculation is enough? It is accepted by the engineering community (and demonstrated through testing) that pumping the equivalent of the total volume of the pool through the filter and treatment system once does not complete the job. In fact, only about 40% of the water will even enter the system. Send two equivalent volumes through the system and between 80 and 85% of the pool water will actually be treated. Each such cycle is called a turnover. Experience has led most health departments to require a minimum of four turnovers per day equivalent to pumping four equivalent volumes through the system daily. Our sample pool of 118,125 galls will therefore require filtering, and treating 4 times its nominal volume, or 4 x 118,125 = 472,500 gallons per day; And this is the minimum! If your pool is not kept clean and sparkling with this turnover and treatment, it will require MORE recirculation and treatment. In the case of spas, therapy pools, waterslides, and wave pools, the tremendous influx of dirt and other contaminants may require a turnover rate of 30 minutes or less. Basically, the pool or spa water must be filtered and treated as often as required to keep it clean a sanitary. All swimming pools shall be equipped with a recirculation system which, at a minimum, consists of a pump, a filter, connecting piping, fittings, valves, disinfecting equipment, necessary pipe connections to the inlets and outlets, a skimmer and/or overflow gutter and main drains. A separate recirculation system shall be provided for each swimming pool. The recirculation system shall be designed to accommodate the following required maximum turnover time: Wading pool, two hours and any other swimming pool, six hours High Sierra Pools, Inc Page 7

8 Adequate provisions shall be made for backwashing and/or cleaning of all filters 2.2. Filter Room Swimming pool facilities shall have a room(s) or structure which encloses the filtration equipment, pumps, electrical equipment, chemical feed equipment, and other recirculation and filtration system appurtenances. The room(s) or structure shall provide working area and access above and around all equipment no less than that specified by the manufacturer and sufficient to permit routine maintenance. The room(s) or structure shall be provided with a lockable door(s) of sufficient width to permit the removal of equipment. The entrance to the filter room(s) shall be easily accessible from the deck so the pool operator can enter the room(s) without having to exit the enclosed pool area. The room(s) or structure shall be impervious to water and resistant to the chemicals necessary for the operation of the facility. The floor of the filter room(s) or structure shall be designed to provide adequate drainage with a minimum floor slope of one to 48 and a maximum floor slope of one to 24 to a floor drain and shall be kept dry at all times, particularly in the vicinity of electrical panels. Discharging filter backwash water onto the floor is prohibited. The filter room(s) shall be provided with mechanical cross-ventilation. Illumination of at least 30 foot-candles, measured 24 inches above the floor, shall be provided above equipment and working areas. A minimum of two light fixtures shall be installed, and all light fixtures shall be shielded Circulation and Recirculation Equipment Pool Outlets Overflow Gutters and Skimmers Overflow water passes through gutters or skimmers equipped with strainers to remove large floating debris. These must be cleaned manually on a regular basis to maintain flow. The frequency of cleaning will depend on the debris collection in the fall, floating leaves can block a strainer very quickly. Gutters operate by accepting water spilled over their lip, and then carry the water to one or more strainers where they connect to the drainage piping. Skimmers include a flap-like gate called a weir that prevents water (and debris) from returning to the pool, making them more effective at catching and holding floating debris. Overflow gutters or skimmers shall be provided on the vertical wall(s) of all swimming pools, and designed to adequately skim the pool surface. The overflow gutter or skimming system shall be capable of continuously removing 80 percent or more of the re-circulated water and returning it to the filter. Where overflow gutters are used, they shall extend completely around the swimming pool except at steps, recessed ladders, ramps, and stairs. The overflow gutter shall be designed to serve as a handhold. Overflow gutters having a surge capacity less than one cubic foot per linear foot of pool perimeter shall be indirectly connected to the recirculating system through a properly sized and designed surge tank/balancing tank with a minimum surge 2014 High Sierra Pools, Inc Page 8

9 capacity of one gallon per square foot of water surface area. Overflow gutters having a surge capacity of one cubic foot, or greater, per linear foot of pool perimeter shall be connected to a properly sized and designed balancing tank. The gutter, drains and piping draining to the surge tank/balancing tank shall be designed to rapidly remove overflow water caused by recirculation, displacement, wave action or other causes produced during the maximum swimming pool load. The opening into the gutter beneath the coping shall not be less than four inches and the interior width of the gutter shall not be less than three inches. Where gutters are used, they shall be designed to prevent patron entrapment or injury. The overflow edge or lip shall be rounded and not greater than 2½ inches thick for the top two inches. The overflow outlets shall be provided with outlet pipes at least two inches in diameter. The outlet fittings shall have a clear opening in the grating at least equal to 1½ times the cross-sectional area of the outlet pipe. Where skimmers are used they shall be provided at the rate of one skimmer per 40 feet of pool perimeter or fraction thereof, or one per 400 square feet of pool water surface area or fraction thereof, whichever is greater. They shall be spaced so as to provide maximum skimming action of the pool surface. 1. Skimmer throats shall be no greater than the width required for ten-inch weirs. 2. Skimmer weirs shall be automatically adjustable to variations in water level over a minimum range of four inches. 3. A removable basket or screen to entrap large matter shall be provided in each skimmer. 4. The flow rate through the skimmer shall not be less than 20 gallons per minute, nor greater than 35 gallons per minute. Each skimmer shall be provided with a means of adjusting the flow through the skimmer. 5. Skimmer systems shall be designed so that all skimmers are interconnected. 6. Skimmer lids shall be securely in place at all times. Main Drain Outlets The main drain, or bottom outlet, is designed to remove debris of whatever kind that settles to the bottom. It is sized to accommodate at about 25% of the desired flow rate (turnover rate) for the pool, while not creating enough suction at the grate to injure a swimmer. Main drain outlets should comply with following: All swimming pools shall have a minimum of two interconnected main drain outlets, that cannot be isolated by valves or other means, for each recirculation pump system. Main drain outlets shall be located in the deepest part of the pool. All piping associated with the main drain outlets shall be of equal diameter and each main drain shall be of equal size. Main drain outlets and associated piping shall be hydraulically designed to provide equal flow though each main drain outlet. A main drain outlet shall be no less than three feet and no more than 20 feet from another main drain outlet, and no more than 15 feet from a pool side wall. A main drain outlet opening shall be covered with a protective grate or anti-vortex cover which is not hazardous to patrons, is anchored in accordance with the manufacturer's specifications and recommendations, and is designed to prevent body entrapment or injury. Main drain grates or covers shall be secured so that their removal requires the use of tools. Main drain covers shall be manufactured and installed according to the specifications set forth by the ASME/ANSI and NSF International standards for suction fittings. The cover, frame, and all components shall be corrosion resistant and shall be designed to withstand the maximum anticipated forces generated by active use. The total water velocity through main drain outlets shall not exceed 1½ feet per second for water depths eight feet and greater or one foot per second for depths less than eight feet, and shall not exceed the maximum flow rate specified by the manufacturer of the main drain cover High Sierra Pools, Inc Page 9

10 A suction cleaner shall be provided. Where a suction cleaner is operated by the recirculating pump, a device or devices shall be provided for regulating the flow(s) from the pool outlets. The suction cleaner line shall be connected through a hair and lint strainer. Portable electric suction cleaners shall be UL rated and connected to a GFCI protected electrical outlet. Waste from a portable suction cleaner shall be disposed of as solid waste. Hydraulic jet-type suction cleaners shall be permitted in lieu of other suction cleaners if the fresh water pressure is 30 psi or greater and the water service line is provided with an approved backflow preventer. Pool Suction Cleaner A suction cleaner shall be provided. Where a suction cleaner is operated by the recirculating pump, a device or devices shall be provided for regulating the flow(s) from the pool outlets. The suction cleaner line shall be connected through a hair and lint strainer. Portable electric suction cleaners shall be UL rated and connected to a GFCI protected electrical outlet. Waste from a portable suction cleaner shall be disposed of as solid waste. Hydraulic jet-type suction cleaners shall be permitted in lieu of other suction cleaners if the fresh water pressure is 30 psi or greater and the water service line is provided with an approved backflow preventer Pool Inlets Conditioned water is returned to the pool through inlet openings placed to encourage thorough circulation with in the pool. While swimmers will ensure good circulation in the shallow end and near the surface, circulation at the deep end largely relies on the direction and volume of flow from the inlets. Circulation patterns should carry water from the shallow to the deep end while raising water from the bottom toward the surface. All inlets located in pool walls shall be spaced not more than 20 feet on center around the pool perimeter. When inlets are located in the pool bottom, the number of inlets and their location shall be designed to insure the proper distribution of filtered water. The minimum number of bottom inlets shall be determined by dividing the perimeter of the pool, in feet, by twenty. All wall inlets, except makeup water inlets and wading pool inlets shall be at least 15 inches below the operating water level of the pool, except for prefabricated gutters with 45 degree angle inlets in the bottom. Each inlet shall be provided with a means of adjusting flow, through a range of at least 50 percent of its design capacity. Inlet flow controls shall be readily accessible. Strainers Strainers are used in two areas at the skimmers and just before the inlet to the pump. The skimmer strainer is designed to catch floating debris where it can be easily removed by the pool operator. It is important to maintain the hair/lint strainer gasket in good condition and the strainer lid always have to be sealed. If any damage to the strainer gasket or lid there will be air bubbles visible coming from the return outlet. Engineers will call the latter a nut and bolt strainer it is designed to prevent anything that might damage the pump from entering it. This strainer removes any debris from the bottom drain such as sand, hair, lint, hairpins, and similar solid matter -- before the water enters the pump. As this strainer becomes clogged, the inlet pressure to the pump will drop. If the strainer is not serviced as soon as the pressure begins to drop, pump damage can result. Both strainers must be serviced on a regular basis High Sierra Pools, Inc Page 10

11 Pumps Swimming pools most commonly use centrifugal pumps. These pumps accept water into the center, or eye, of an impeller that resembles a flat disc with curving projections on the side facing the inlet. These projections extend from the face of the disc toward (but not touching) the casing and curve outward from the center opposite the direction of rotation of the pump. Water enters at the center, and then is impelled outward by the rotating impeller toward the pump outlet. The outlet (also called the volute) is slightly larger in cross section than the impeller housing, which converts the velocity within the pump to pressure. A removable and re-installable pump(s) shall be installed with adequate capacity for the required turnover time. Whenever possible, pump(s) shall be so located as to eliminate the need for priming. If the pump(s) or suction piping is located above the overflow level of the swimming pool, the pump(s) shall be self-priming. The pump(s) shall be capable of providing a flow adequate for the backwashing of filters. Pumps shall be securely supported. Centrifugal pumps are rated by flow rate and pressure. To achieve the required turnover rate, MINIMUM FLOW RATE formula is used: Minimum Flow Rate (GPM) = Pool Volume / Turnover Rate / 60 (min) Pool volume of a rectangular pool can be calculated as length (in ft) x width (ft) x average depth (ft) x 7.5, result is in gallons. All pressure filter systems shall have a hair and lint strainer. The hair and lint strainer baskets shall be corrosion resistant with openings not exceeding 1/8 inch in size, which provide a free flow area of at least four times the area of the pump suction line at the strainer connection, and shall be accessible for frequent cleaning. An extra hair and lint strainer basket shall be provided for each hair and lint strainer. As pressure increases, flow rate drops. Backpressure from the filters, piping, and even the pool inlets can slow the flow rate dramatically. As filters are extracting fine dirt, the pressure to maintain flow through the filter media increases, and the flow rate decreases. Resistance in a pool circulation system is caused by friction and head loss. In order to ensure that the pump will create enough flow for the required number of turnovers per day, it must be large enough to maintain the desired flow even when the filters are dirty, nearly ready for backwashing. All of these criteria entered into the design of the pump before it was purchased and installed. The pool operator needs only to understand that increasing pressure means decreasing flow both indicate that the filters are being clogged. A very real safety factor with centrifugal pumps is that they can continue to run without damage even when the outlet valve is closed. The impeller will simply spin in the housing, producing the pump s maximum pressure. This allows the operator to valve off the pump briefly to switch from one filter to another or to throttle the flow while arranging for a filter backwash operation. Surge Tank A surge tank sized to accommodate the overflow due to entry of the maximum allowable number of swimmers at one time is included in most pool designs. This tank accepts overflow water when swimmers are in the pool to hold it rather than send it to the drain High Sierra Pools, Inc Page 11

12 The tank is equipped with an overflow outlet as well, so in the unlikely event that there is excess water it can overflow into the drain. Make-up water is added here as needed, via a water supply operated by a float valve. If the water level drops below the established minimum, the float valve opens and fresh water is added. The inlet pipe stops 6 inches above the maximum water level in the tank and is protected by a check valve to prevent pool water from entering the supply system Piping The piping is designed and specified prior to construction to provide proper flow rate. The only time piping needs to be changed is during repair, adding a new or different filter, or when a pump is replaced. Pool piping is sized to keep the flow velocity below 8 feet per second on the discharge side, while the suction piping (feed to the pump) is sized for not more than 6 feet per second. Since the pipe, valves, elbows, flow meters, and other fittings all add friction, increasing the pressure required to maintain flow, the pipe and fittings may need to be quite large to provide the desired flow velocity. The piping system for swimming pools shall be composed of NSF International listed materials or their equivalent designed for the following operations: filling the swimming pool;; re-circulating the pool water through the treatment equipment; backwashing or washing each filter to waste;; operating a suction cleaner (if provided);; emptying the pool;; and draining the system. In addition, the piping system of any swimming pool containing a hydro-jet system or water conditioning system shall be composed of NSF International listed materials, or equivalent, which are capable of supporting such systems. There shall be no direct connections between the swimming pool recirculation system and the sewer or potable water supply. Fill spouts, when installed, shall be located under diving boards, under guard chairs, adjacent to pool ladder handrails, or otherwise protected to preclude a tripping hazard and shall be properly supported if not inherently self-supporting. Fill spouts shall not project into the space above the pool water surface by more than two inches beyond the edge of the pool. Cross-connections shall be prevented by providing an air gap between the highest possible flood level of the pool and the pool fill spout. The air gap shall not be less than two fill spout pipe diameters or less than six inches. An approved backflow preventer may substitute for the air gap. The system shall have a means of discharging filter backwash or other pool water to waste as follows: 1. Waste from backwashing or draining of a pool shall be discharged in a manner approved by the Director. When only a sanitary sewer is available to a swimming pool, the rate of discharge is subject to the approval of the appropriate authority for sanitary sewers and treatment facilities. 2. An air gap or air break to prevent a cross-connection between waste discharge piping and recirculation piping shall be provided. 3. Discharge receptor and piping of sufficient size to accept backwash water and prevent back flooding. 4. A sight glass in the backwash discharge line in a readily observable location. 5. In the event the backwash waste pipe will not accommodate the backwash flow, the design and installation of a holding tank shall be required. The holding tank shall be sized to contain 110 percent of the volume of water required to adequately clean the filter(s) at the backwash flow rate and length of time specified by the filter manufacturer. 6. The visible piping system shall be securely anchored, supported or braced, unless inherently self-supporting, and marked with permanent tags, labels or 2014 High Sierra Pools, Inc Page 12

13 markings to clearly identify the direction of flow and shall be color coded as follows: Freshwater blue (to check valve) Backwash black Influent yellow Effluent white Suction cleaner orange (to control valve) Recirculation green (Auxiliary recirculation not part of the filtration system; such as, but not limited to, water features, jets, fountains, waterfalls, aeration systems or similar features) Heater piping red (to nearest isolation valves) All piping shall be designed to minimize friction losses and to carry the required quantity of water at a velocity not to exceed eight feet per second for copper discharge piping, and ten feet per second for discharge piping other than copper. Suction velocity for all piping shall not exceed six feet per second. Pipe suction velocity may also be limited by the maximum flow rate specified by the manufacturer of the suction outlet covers installed in the swimming pool. All piping and appurtenances included in the recirculation and filtration system shall be inspected and approved by the Director prior to covering. All piping shall be tested at the time of inspection to at least 25 psi of pressure. All subsurface pool piping shall be imbedded in and covered with sand or an approved equivalent. All valves shall be clearly identified with permanent markings or tags which are referenced by a pool water recirculation system operation manual and/or placard Valves Valves control water flow, varying from permitting full flow when completely open to stopping flow when closed. Intermediate positions of the valves adjust flow to the desired rate. Every piece of equipment in the system needs manually operated valves on both the inlet and exit sides to permit totally stopping the water during maintenance when needed. Ball, gate, butterfly, and float valves each serve a different purpose. a) Ball Valve A Ball valve consists of a steel or plastic ball closely fitted within housing and a stem extending from the ball through the housing with a lever attached to turn the ball. The ball is drilled through with a passage the same internal diameter (ID) as the piping that it controls. When the ball is in the open position, there is no impediment to flow. When the lever or handle is turned 1/4 turn, the ball rotates to close the valve completely. A ball valve introduces almost no friction in flow when it is fully open. A modification of this valve, the three-way valve, has a side channel drilled from one side only into the main thru-channel; this permits the valve to direct the flow straight thru or deflect the flow to a secondary pipe. Three-way valves are often used to control flushing and backwashing of filter systems. b) Multiport valve A Multiport valve is described by its name. These valves are based on ball valves, but have multiple passages in the ball and/or several different inlet or outlet pipes. The internal passages align with different inlet and/or outlet pipes as the ball turns, changing the direction of flow. The three-way valve mentioned above is an example of a multi-port valve High Sierra Pools, Inc Page 13

14 The most typical use of a multiport valve is controlling flow around the filters. A three-way valve has passages that look like a T if you could see through the ball or core. In one position, the water enters through the leg of the T and exits along one side of the crossbar into the filter in normal direction, so it is filtered and re-circulated back to the pool. Another position reorients the valve so the water exits the valve into the backwash piping. If the valve is turned so the water bypasses the filter, the valve is said to be open. In the closed position, no water flows through the valve. c) Gate Valve Gate valves are built just as their name indicates. A slightly tapered disk fits snugly into housing; when seated, it stops flow. When fully open, it permits maximum flow. However, this type of valve introduces addition friction and turbulence to the flow. A gate valve is used in locations where flow adjustment is needed; the disk is attached to a screw and large, round valve handle (wheel). As the wheel is turned, the valve disk moves opening or closing only a little bit at a time. This valve is ideal for adjusting flow. d) Butterfly Valve A butterfly valve is sort of a cross between a ball and a gate valve. The valve portion is a flat disk (butterfly). It is mounted to a shaft passing through the housing in the center of the flow; when the shaft is turned, the butterfly moves to or from a vertical position within the housing. When partially open, it also adjusts flow. A butterfly valve will permit flow around two sides of the disk, while a gate valve only permits flow around one side of the disk. A butterfly valve may therefore generate less friction and turbulence, but like a ball valve it is not as good as a gate valve for adjusting flow rate. Butterfly valves are often used as the operating portion of a float valve. e) Diaphragm Valve A diaphragm valve has a thin plastic or metal plate (the diaphragm) centered in the valve housing between a screw-activated pressure rod and the inlet opening of the valve. It is activated by turning the screw. As the handle or wheel is turned toward the closed position, the diaphragm is pressed against the inlet opening, closing it. As the handle is turned toward the open position, the diaphragm moves away from the inlet opening and flow resumes. Diaphragm valves are most often used in chemical treatment systems or with float valve systems. f) Float Valve Float valves are operated by a floating chamber attached by a fairly long, light-weight rod attached to the operating portion of the valve. As the water level drops, the float drops with it opening the valve. When the level rises, the float rises with it closing the valve Flow Rate Indicator Three types of flow rate indicators (flow meters) are in common use. The simplest is the variable area flow rate indicator. It consists of a vertical glass or plastic calibrated tube with a floating indicator of a specific weight inside the tube. The unit is installed in series with the flow to be measured. An orifice plate is installed in the main flow to divert a small quantity of water from the main flow through the flow meter. The flow through the meter lifts the ball to show the rate of flow. Flow meter indicators are calibrated in gallons (gpm) or liters per minute based on the size of the orifice plate and the pressure in the system High Sierra Pools, Inc Page 14

15 The mercury manometer operates by measuring the pressure differential across an orifice plate. In this case, no water is diverted a manometer measures the pressure differential rather than flow. The manometer itself has a tube calibrated in gallons or liters filled with mercury and water. A reservoir for each is provided at the bottom of the manometer. The pressure differential across the orifice plate is transferred to the manometer by small connections on each side of the plate; the partial vacuum created draws the heavier mercury up into the tube, displacing some water. The height of the mercury column is directly related to the vacuum created. Again, the tube is calibrated in gallons or liters per minute flow. The most modern flow meter is electronic. A paddle wheel rotates in the water as it flows through the pipe, while a magnet or series of magnets induce a current in the meter. The unit is calibrated for the system in which it is installed, and can provide a digital readout and direct recording either on a chart or into a computer. All flow meters must be installed in relatively long, straight runs of pipe where the flow is smooth and regular to deliver useful readings. The flow rate should never be allowed to drop below the design standard. In general, the recirculation system shall have a flow meter on the return line to measure the flow of filtered water being returned to the swimming pool. The flow meter shall be of fixed calibration, shall measure in gallons per minute, and shall be properly sized to indicate the design rate of flow at approximately mid-scale Flow Controllers Flow controllers are automatic valves connected to flow meters. The valve opens or closes depending on the input from the meter. They can control flow very accurately. Flow controllers are used to compensate for increasing pressure and reduced flow as filters become partially blocked; as the pressure increases, the flow controller opens the valve to decrease internal system pressure at the pump and increase flow. The same device may also signal when the valve is wide open meaning the filter needs backwashing Pressure and Vacuum Gauges Using pressure gauges on a pool system is like taking a blood pressure on a person they gauge how well the system is working. In a pressure system (filters under pressure), the differential pressure read from a gauge before and after each filter is used to determine when the filter must be backwashed. In a vacuum system (filters under partial vacuum), the effluent pressure (vacuum) gauge and the flow are used to determine when the filter is becoming clogged. The filter system shall be provided with a minimum of one influent pressure gauge for each filter and one effluent pressure gauge following the filter system. Recirculation system pumps shall be fitted with a vacuum and pressure gauge installed as near as practical to the pump suction and discharge pipe connections. All pressure gauges shall measure pressure directly in pounds per square inch (psi). Vacuum gauges shall measure in inches of mercury. Gauges and flow meters shall be readily accessible and clearly visible, shall be in good repair, and shall be located and installed according to the manufacturer's specifications and recommendations; 2014 High Sierra Pools, Inc Page 15

16 Heater Most pools require some form of heating to maintain the water at a comfortable temperature. This is readily accomplished with: - electric heaters - gas heaters - steam heaters Chemical Treatment Equipment Small tanks and pumps for soda ash and acid for ph balance and injector(s) for chlorine can add necessary treatments directly into the effluent line following the filters. Manual chemical treatment can be made directly to the pool (when no one is swimming) before the pool opens. Swimmers need to remain on the deck for at least 30 minutes after manual chemical treatment applied Filter Systems There are two basic types of filter system pressure and vacuum. A vacuum system has the filter before the pump; as water is drawn into the pump, a slight vacuum is drawn on the outlet of the filter. Gravity and the differential between atmospheric pressure and the outlet pressure (vacuum) push water through the filter. Since this pressure differential is relatively small, a vacuum system requires larger or more filter tanks than a pressure system. A pressure system has the filter(s) after the pump. Pressure across the filter can therefore be higher, resulting in a higher flow rate per square foot than that in a vacuum system. A pressure system is usually the least expensive to purchase, use, and maintain. See chapter on Filters and Filtration for more complete discussion of filter operation Filters and Filtration Filtration is the physical process of removing suspended particles from the pool water. Swimming pools and spas are constantly being contaminated with algae, bacteria, chemicals (including suntan oils and lotions), hair, leaves and grass, makeup, sand, and other debris. Solid matter, however finely distributed, must be removed continuously. Filtration is the removal of the solid contaminants by passing the water through media with holes or passageways smaller than the particulates in the water. Types of filtration equipment include gravity/vacuum filters usually with sand or carbon media and pressure filters. Pressure filters may use sand, diatomaceous earth (DE), synthetic fabrics, and foamed plastic cartridges. Cartridge filters are highly effective; they can be constructed to match specified pore sizes for maximum flow or filtration capacity. Sand filters are depth filters they collect the largest particulates on the surface and smaller particulates within the sand bed. Foamed plastic cartridge filters are also depth filters, while accordion-pleated synthetic fabric cartridges and DE are surface filters. The flow required to achieve an acceptable turnover rate was discussed in the chapter on circulation. Filters and filtration systems are rated on their flow rate in gallons per minute (gpm) per square foot of surface area. Obviously, if you need a high flow rate, you also need a large surface area. The requirement on sizing of number of filters and filtration area is given by following formula: 2014 High Sierra Pools, Inc Page 16

17 Filter Area = Flow Rate / Filter Media Rate Both health department regulations and manufacturers specifications state the maximum flow rate for each filter system. Filtering efficiency is always better when the filter surface area is greater than that required. Filters and systems vary greatly in size. Each is engineered to filter the size pool where it is installed. The pool operator needs to know how to maintain their filters for maximum filtration efficiency. A detailed information sheet or placard with all the operating information should be posted near the filters where it is visible at all times. For best results, a checklist or report form that duplicates the placard should be used to record all filter maintenance activities Filters Gravity Filters Gravity Sand (Vacuum Sand) As noted in Chapter 2, the turnover rate for our sample pool is 472,500 gallons per day or 328 gpm. An older pool may still use a gravity sand filter system with a flow rate of 1 gpm/sq. ft. or less. This would require a MINIMUM surface area of 328 sq. feet. In a rectangular layout, this filter would have to be 20 feet long x 16 feet wide. Gravity sand filters are just that they are filled with sand, and operate by gravity. A gravity system filter tank must be below the bottom of the pool or supplied by a feed pump. Filtered water is collected by a system of pipes under the grating or decking supporting the sand, then pumped back into the pool. The pumping action develops a vacuum that assists the flow through the filter. Backwashing this system requires much more flow than would be required for the circulation pump about 15 gpm per sq. ft. If this minimum sand filter for the sample pool (328 sq. ft.) were a single tank, the MINIMUM pump size would be 328 x 15 = 3570 gpm. These gravity filters often have several chambers that can be backwashed independently, which reduces the necessary pump size. The backwash water overflows to waste. Construction costs for such filters prohibit their use in new pools, but there are a few old pools that still use this system. Municipal water treatment facilities often use gravity sand filters in conjunction with flocculating agents. Rapid Sand (sand and gravel) So-called rapid sand filters consist of a tank with a pumped supply of water from the pool fed through a distribution header with the tank. The tank has a collection manifold near the bottom to accept the filtered water and direct it through a return pump back to the pool. The tank is filled with several layers of gravel of decreasing size followed by a 12 to 20 inch deep layer of sand. The tank has a space above the sand equal in size to the depth of the sand to allow fluidization of the sand bed without losing the sand to the drain. There is an air vent in the top of the tank. Water inflow is controlled to keep the tank as full as possible without overflowing through the air vent. A typical flow rate for a rapid sand filter is about 3 gpm per sq. ft. Since our sample pool requires not less than 328 gpm flow rate to achieve the required turnover rate, the rapid sand filter system would require = sq. ft of surface area. As dirt accumulates inside a filter the amount of water that can pass through the filter A single cylindrical tank to handle this flow would be 12 feet in diameter. As dirt accumulates inside a filter the amount of water that can pass through the filter decreases and backwashing is necessary High Sierra Pools, Inc Page 17

18 Backwashing is the process of reversing water flow to remove accumulated particles from inside a sand filter. Since filtration is impossible during backwashing, most installations use at least two tanks. A filter backwash cycle for a sand filter is complete when the backwash water appears clear in the sight glass. A cylindrical tank of half the diameter (6 feet) has only 28 sq. ft. of surface area. Four 6 foot diameter tanks would be required to service our sample pool. High-Rate Sand Pressure Filters A high rate sand (pressure) filter can handle up to 20 gpm per sq. ft., requiring only 16.4 sq. feet of surface area for our sample pool. Let s do the math together and input the constants into the formula from previous page. Filter area = Flow Rate / Filter Media Rate = 328 gpm / 20 gpm per sq. ft = 16.4 square feet This means much smaller tanks, quicker and easier backwashing, and less loss of water during backwashing. A single cylindrical filter of this type would need to be about 5 feet in diameter. Again, it would be several feet tall to accommodate the sand, support grid, and the inlet and outlet manifolds. These systems use finer sand than the gravity systems and the outlet manifold has many openings smaller than the sand to permit collection and outflow of the high volume of water. There is no gravel. Backwash is at the same rate as filtration in this case, up to 20 gpm. This is a highly efficient, cost-effective system able to operate quite well with only one or two filter tanks. The sand is not lost during backwashing, so cleaning the filter and restoring it to operation takes minimal labor and no new supplies. An elevated reading from the vacuum gauge on the top of a high rate sand filter may indicate that the hair/lint strainer needs to be cleaned and filters backwashed. Cartridge Filters Cartridge filters consist of a tank with inlet and outlet and a number of internal mountings for cylindrical cartridges made of the selected material and pore size. Their mounting inside the housing forces water to enter the tank outside the cartridges, pass through the cartridges, and then exit the housing. The cartridges most used in pool operations are similar to automotive oil filters, in that they consist of a synthetic fabric with multiple folds mounted over a support medium, such as stainless steel mesh. This design provides a very large surface area in a small space. These filters resemble DE cartridge type filters, except no filter media is required. Cartridges are surface filters, rated by surface area and pore size. The pore size indicates the largest particulate that can pass through them. For example, a 20 micron filter will only pass particulates smaller than 20 microns when new. As contaminants are collected on these filters and clog the pores, the maximum particle size that can pass through them decreases and the flow rate drops. When the flow rate drops too far, the cartridges must be cleaned or replaced. Cleaning is time-consuming, so it is almost mandatory to have at least two complete sets of filters. One set is in use while the other is being washed or soaked in cleaning solution (trisodium phosphate (TSP) or similar). The filter rate of cartridge filter is gpm/sq. ft. Cartridge filters do not pass oils if they are first wet with water. As a result, oils collect on their surface along with the dirty solids. To clean them, first wash them off with a strong, 2014 High Sierra Pools, Inc Page 18