CIPHI 2017 Annual Education Conference

Transcription

1 CIPHI 2017 Annual Education Conference Michael Wu, M. Sc., P.Eng. Public Health Engineer, VCH Jessica Ip, BSc(Hons), MBA, CPHI(C) Senior Environmental Health Officer, VCH

2 Pool Suction Hazards Contents What are suction hazards Velocity calculations VCH survey results VCH survey lessons learnt VCH CP Waiver process

3 Types of Entrapment Hair Limb Body Disembowelment Mechanical (items caught)

4 Types of Entrapment Source: Technical Committee Report on suction Outlet Safety and Effectiveness of ANSI/ASPS-7

5 Suction Hazards Mitigation Proper pool main drains + <1.5 ft/s through the main drains

6 Suction Hazards Mitigation Proper Drain Covers 6

7 What s Wrong? Broken drain cover

8 Missing drain cover What s Wrong?

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10 Not a BC requirement but no other cover available changing out old covers no like for like

11 Proper Drain Covers

12 Manufactured Sump Sump/cover compatibility needs checking when covers are changed

13 Field Installed Sumps (To be designed by P.Eng.)

14 Suction Hazards Proper Flow Meters 14

15 Flow Measurement By monitoring pump performance Total Dynamic Head: measurement of the system s resistance to flow Challenges: Need to reference back to pump curve Pump curves may not be accurate over time Solution Install flow meters on each line 15

16 Flowmeter Requirements Flow Meter on Return Line Flow Meter on Return Line Main Drain Main Drain Skimmers Play Equipment or Hydro-jet Pump Main Recirculation System Pump

17 Pitot Tube Flowmeter

18 Pitot Tube Flowmeter

19 Digital Flowmeter

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24 Suction Hazards Proper Flow (<1.5 ft/s) 24

25 Mathematics..

26 Pool Math 101 Velocity = Flow Rate / Open Area

27 Pool Math 201 Velocity = Flow Rate / Open Area Total flow rate (USGPM) X ft 3 X 144 in2 X 1 min Drain cover open area (in 2 ) US Gal 1 ft 2 60 sec = Total flow rate (USGPM) / Drain cover open area (in 2 ) x 0.32 = Flow Velocity (ft/s) Conversion factor : X 144 =

28 Pool Math 301 Flow Rate (recirculation + hydro jets) Entrapment Risks Velocity thro Main Drain (1.5 ft/s) Filtration Rate (15 usgpm /sq ft) Water Quality Issues Turnover (30 min to 12 hours) Water Quality Issues?

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30 Solutions for Pools with Single Main Drain

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33 VCH Pool Suction Hazard Survey Background: BC Pool Regulation changed to 2012 Compile record of all pool datasheets Initial training by PH Engineer for all EHOs Did an inventory of all pools in the HA Inform operators of pending requirements

34 Background (cont d) Inventory includes: o Mitigation strategy developed by PH Engineer o Training session by Public Health Engineer o Started on abatement action targeting pools with single main drain and single skimmer during routine inspections

35 Mitigation Strategy: No main drain Single main drain Scenarios Short-term options Long-term options Single skimmer None Ensure the skimmer covers are vented and the velocity over the Multiple skimmers skimmer weirs are no more than 5USGPM/in (7.5L/min/cm) Single skimmer Multiple skimmers Install VGB compliant drain cover or enlarge the main drain Install VGB compliant drain cover or enlarge the main drain or Block the main drain; ensure the skimmer covers are vented and the velocity over the skimmer weirs are no more than 5USGPM/in (7.5L/min/cm) Install proper multiple main drains or Install a VGB compliant drain cover and sump together with a Safety Vacuum Release System

36 Criteria used on Inspection For Single Main Drain, Single skimmer pools et al: 1. Does pool has functioning flow meter(s)? If no, and cannot determine the flow; give a week to install/fix flow meter, if not possible, pool will be closed (health hazard unknown). If yes, obtain the flow. 2. What is the flow? Exceeds 1.5 ft/sec., pool will be closed immediately - suction hazard. Does not exceed 1.5 ft/sec., does it have a VGB compliant cover? If yes to both - the pool is considered short term compliant & allowed time to plan for long term mitigation strategy If yes, and no - install VGB compliant cover (or enlarge drain) - short term compliant & allow time to become long term compliant. Timeline ~ 18 months. Condition is moving towards being long term compliant. No drop dead date

37 Efforts Continued Tracking progress using a spreadsheet. A follow up to the initial 2011/2012 Inventory Designed a one-time Survey using our Inspection system (Hedgehog) for the entire HA. Flow meters & functioning meters Main drain covers, VGB compliant? Velocity through main 1.5 ft/sec?

38 2016 Survey Results: 1. Velocity through main drains # Pools with flow data <1.5 ft/s >1.5 ft/s Not reported Total Pools in survey 2016 # pools % in compliance 95% 5% 13%

39 2. Flow meters installed 2016 Total in survey Meter installed No Meter Not Reported # pools % installed 94% 5.8% 0.2%

40 Flow meters conditions Flow meters Functional Non-functional Not reported % <1 Flow meters Correctly Installed Installed Wrong Not reported %

41 3. Covers for Single Main Drain 2016 Total pools # Pools with single main drain # pools non-vgb VGB cover cover # % not reported

42 Covers for Dual Main Drains 2016 # pools # Pools with dual drain Total # # pools non-vgb not pools VGB cover cover reported # pools %

43 Summary - Drains & Covers 17% 5% 2% pool with dual main drains + VGB covers pool with dual main drains + non VGB 3% 24% 49% pool with dual main drains + unknown cover Pool with single main drain + VGB cover Pool with single main drain + non VGB cover Pool with single main drain + unknown cover

44 The Good News VCH Total (2012) VCH Total (2016) Total (hot tubs and swimming pools) Number of pools % with dual main drain reported % with flow meter installed Hot tubs only Number of hot tubs % with dual main drain reported % with flow meter installed Swimming Pools Number of swimming pools % with dual main drain reported % with flow meter installed 53 96

45 Knowing what to look for!

46 Not-so-Good News Not Velocity # pools <1.5 ft/s >1.5 ft/s reported Overall compliance = 83% 4% 13%

47 Way Forward Continue effort : to determine if the velocity flowing through the main drains are less than 1.5 ft/s (46cm/s). And, to mitigate risks of potential suction entrapment hazards.

48 Best Practice Guide No main drain Single main drain Scenarios Short-term options Long-term options Single skimmer None Ensure the skimmer covers are vented and the velocity over the Multiple skimmers skimmer weirs are no more than 5USGPM/in (7.5L/min/cm) Single skimmer Multiple skimmers Install VGB compliant drain cover or enlarge the main drain Install VGB compliant drain cover or enlarge the main drain or Block the main drain; ensure the skimmer covers are vented and the velocity over the skimmer weirs are no more than 5USGPM/in (7.5L/min/cm) Install proper multiple main drains or Install a VGB compliant drain cover and sump together with a Safety Vacuum Release System Ref: Table 1, Best Practice Guide for Mitigating Suction Hazards in Pool, HARWC June 2015

49 Recommendations - by PH Eng. Encourage operator to monitor flow & maintain flow meters Set priorities: Pools with NO main drain but single skimmer pose extra risk immediate focus to reinstate main drain & check skimmer operation closely Pool with single main drain, non VGB cover install VGB covers & check skimmer operation closely Non-VGB cover for any pools likely due for replacement Eventually, need to install dual main drain or SVRS

50 Lessons Learnt No easy task! Takes a long time Training is definitely necessary (internal & external ) Tracking progress is good Overall doing well but need to continue It gets easier, and It will get done

51 CP Waiver Process 2016 Create a step by step process to encourage best practice to mitigate suction hazard, and Provide oversight To track changes Organized an information session in 2016, plus continual dialogue with pool service companies

52 CP Waiver form

53 Pictures of measurements

54 Outcome Found CP waiver process to be labour intensive for HA Assessment could end up requiring a CP Will need to evaluate whether to continue to have a CP waiver process

55 Thank you for your attention

56 Questions?