SAQA All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.
SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD: 

Install and maintain irrigation pressure vessels 
SAQA US ID UNIT STANDARD TITLE
336016  Install and maintain irrigation pressure vessels 
ORIGINATOR
SGB Ornamental Horticulture and Landscape 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 01 - Agriculture and Nature Conservation Horticulture 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 3  NQF Level 03 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Reregistered  2018-07-01  2023-06-30  SAQA 06120/18 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2024-06-30   2027-06-30  

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.  

This unit standard does not replace any other unit standard and is not replaced by any other unit standard. 

PURPOSE OF THE UNIT STANDARD 
A person credited with this Unit Standard will be able to:
  • Utilise knowledge of hydraulics to solve maintenance issues on pressure vessels.
  • Pre-charge and install a hydrosphere in an automatic pump station.
  • Install a hydro pneumatic pressure vessel and its air charging equipment.
  • Conduct preventative maintenance inspections on pressure vessels.
  • Strip, inspect and replace the serviceable components of a hydrosphere. 

  • LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
    It is assumed that learners are competent in:
  • Communication at NQF Level 2.
  • Mathematical Literacy at NQF Level 2. 

  • UNIT STANDARD RANGE 
    N/A 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Demonstrate an understanding of the hydraulic principles that pertain to the installation and maintenance of pressure tanks. 
    OUTCOME RANGE 
    The range includes but is not limited to:

    Compressibility of water, minimal volumetric differences, compressibility of gasses, role of a pressure vessel, water's absorption of gasses under pressure, hydro-pneumatic pressure vessel, hydro-pneumatic pressure vessel, functions of a bladder/diaphragm. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The reasons why, for practical purposes, irrigation water is considered incompressible is explained within the context of the minimal volumetric changes that occur at irrigation pressures. 

    ASSESSMENT CRITERION 2 
    The function of the gas component in a pressure vessel is described within the context of its ability to be compressed and provide the motive energy to generate flow. 

    ASSESSMENT CRITERION 3 
    The benefits of installing a pressure vessel in an irrigation system are described in terms of the roles that a pressure vessel can perform. 

    ASSESSMENT CRITERION 4 
    The phenomenon of gas absorption in a hydro-pneumatic pressure vessel is described and the effect that this has on the volumetric efficiency of the vessel is explained with respect to the reduction of stored energy. 

    ASSESSMENT CRITERION 5 
    The functions that a bladder/diaphragm performs in a hydrosphere/accumulator are explained with respect to the retention of the pressurised gas in the vessel. 

    SPECIFIC OUTCOME 2 
    Identify the potential hazards that pressure vessels pose and the safety precautions that must be adhered to. 
    OUTCOME RANGE 
    Includes but is not limited to:
  • Safety hazards, personal protective clothing, personal protective equipment, legislated safety requirements, safe handling procedures, electrical safety precautions SOPs (Standard Operating Procedures). 

  • ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The safety hazards that a pressurised pressure vessel pose are described in terms of the explosive potential of the stored energy in the vessel. 

    ASSESSMENT CRITERION 2 
    The personal protective clothing and personal protective equipment that should be worn when working with pressure vessels are described in terms of the protection these items afford an artisan. 

    ASSESSMENT CRITERION 3 
    The legislated safety requirements that are mandatory for the use of hydro-pneumatic pressure vessels are described in terms of their applicability to irrigation systems. 

    ASSESSMENT CRITERION 4 
    The safe handling procedures that must be adhered to when moving or transporting precharged pressure vessels are described in accordance with the company's SOPs. 

    ASSESSMENT CRITERION 5 
    The electrical safety precautions that must be followed while conducting work on pressure switches are described in accordance with the Electrical Wiring Codes and the company's SOPs. 

    SPECIFIC OUTCOME 3 
    Install a hydro-pneumatic pressure vessel in a pump station and fit the necessary interconnecting piping and valves. 
    OUTCOME RANGE 
    Includes but is not limited to:

    Characteristics of a hydro-pneumatic pressure vessel, mount on a firm level base, need for regular topping up, ratio of air and water, borehole recharging, surface recharging, air volume control unit, air charger above water level. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The characteristics and operation of a hydro-pneumatic pressure vessel are explained in terms of its "in line" location and rapid response to water hammer and surges. 

    ASSESSMENT CRITERION 2 
    The reasons why a hydro- pneumatic pressure vessel must be mounted on a firm level base are explained with regard to the load carrying capacity and stability that is required. 

    ASSESSMENT CRITERION 3 
    The necessity of regularly "topping up" the air in a hydro-pneumatic pressure vessel is explained with reference to the replacement of the air absorbed by the pressurised water in the vessel. 

    ASSESSMENT CRITERION 4 
    The ideal ratio of air and water in a hydro-pneumatic pressure vessel is described with respect to the optimum energy storage in the vessel. 

    ASSESSMENT CRITERION 5 
    The methods of automatically "recharging" the air in a hydro-pneumatic pressure vessel that operates from a borehole are described and the techniques to install this equipment are demonstrated in accordance with the company's SOPs. 

    ASSESSMENT CRITERION 6 
    The methods of automatically "recharging" the air in a hydro-pneumatic pressure vessel that operates from a surface mounted pump are described and the techniques to install the air charger are demonstrated in accordance with the company's SOPs. 

    ASSESSMENT CRITERION 7 
    The reasons why an air charger must be positioned at a point which is above the water level in the supply tank or reservoir are explained within the context of ensuring that the chargers inlet is not flooded. 

    ASSESSMENT CRITERION 8 
    The role of an air volume control unit is described in terms of its regulation of the air in the vessel and the techniques to install this unit are demonstrated in accordance with the company's SOPs. 

    SPECIFIC OUTCOME 4 
    Install a hydrosphere in a pump station and fit the necessary interconnecting piping and valves. 
    OUTCOME RANGE 
    Includes but is not limited to:
  • Off line connection, pre-charge pressure, benefits of nitrogen, isolation and drain valve to test charge pressure, pressure relief valve-protect vessel from bursting, pressure switch as close to the vessel as possible - quick response. 

  • ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The characteristics and operation of a hydrosphere are explained in terms of its "off line" location and the flexing of its bladder in response to varying pressures. 

    ASSESSMENT CRITERION 2 
    The necessity of pre-charging a hydrosphere is explained in terms of providing sufficient gas storage for the operation of the system. 

    ASSESSMENT CRITERION 3 
    The advantages of pre-charging a hydrosphere with nitrogen rather than air are explained with respect to the presence of oxygen in air and the possible corrosion of the steel vessel. 

    ASSESSMENT CRITERION 4 
    The reasons for pre-charging the vessel to a pressure of 20 kpa less than the "on" setting of the pressure switch are explained within the context of ensuring that the bladder does not collapse inwards when a pumping cycle is activated. 

    ASSESSMENT CRITERION 5 
    The necessity of installing an isolation and drain valve on the feed to a hydrosphere is explained and the methods of installing these are demonstrated in accordance with the company's SOPs. 

    ASSESSMENT CRITERION 6 
    The situations where a pressure relief valve should be integrated into the hydrosphere's inlet manifold are explained in terms of protecting the vessel from bursting in high pressure conditions. 

    ASSESSMENT CRITERION 7 
    The reasons why a pressure switch and pressure gauge should be installed as close to the vessel as possible, are explained with reference to minimising the effects of line surges. 

    SPECIFIC OUTCOME 5 
    Service and maintain a hydro-pneumatic pressure vessel and its air charging equipment. 
    OUTCOME RANGE 
    Includes but is not limited to:
  • Preventative maintenance inspection, pump hunting, waterlogged pressure vessel, borehole charging and air charger. 

  • ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The components on a hydro-pneumatic pressure vessel that require checking in a preventative maintenance inspection are listed and the frequency at which this maintenance should take place is described in keeping with the manufacturer's recommendations and the company's SOPs. 

    ASSESSMENT CRITERION 2 
    The condition in which a pump is considered to be "hunting" is described in terms of the rapid switching on and off of a pumping cycle and the potential damages that this can cause to the pump, motor and electrical switchgear. 

    ASSESSMENT CRITERION 3 
    The ways in which a waterlogged pressure vessel can cause a pump to hunt are explained with regard to the absence of an air cushion in the vessel. 

    ASSESSMENT CRITERION 4 
    The factors that contribute to the water logging of a pressure vessel are listed and the methods of localising and remedying these are demonstrated in accordance with the company's SOPs. 

    ASSESSMENT CRITERION 5 
    The methods of testing and verifying the correct operation of a borehole's air charging components are demonstrated in accordance with the manufacturer's recommendations and the company's SOPs. 

    ASSESSMENT CRITERION 6 
    The methods of testing and verifying the correct operation of an air charger are demonstrated in accordance with the manufacturer's recommendations and the company's SOPs. 

    SPECIFIC OUTCOME 6 
    Service and maintain a hydrosphere in an automatic pump station. 
    OUTCOME RANGE 
    Includes but is not limited to:
  • Preventative maintenance inspection, signs of partial gas loss, signs of total gas loss - pump hunting, removal and replacement of the hydrosphere's bladder, examine inner wall of shell. 

  • ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The components on a hydrosphere that require checking in a preventative maintenance inspection are listed and the frequency at which this maintenance should take place is described in keeping with the manufacturer's recommendations and the company's SOPs. 

    ASSESSMENT CRITERION 2 
    The signs which indicate that a portion of the gas has leaked out of a hydrosphere are described with respect to the time taken for the pressure switch to activate the pump. 

    ASSESSMENT CRITERION 3 
    The signs which indicate that all the gas has leaked out of a hydrosphere are described within the context of a pump's hunting. 

    ASSESSMENT CRITERION 4 
    The methods of testing the charge pressure of a hydrosphere are demonstrated in accordance with the company's SOPs. 

    ASSESSMENT CRITERION 5 
    The techniques for stripping, removing and replacing the hydrosphere's bladder are demonstrated in accordance with the manufacturer's guidelines and the company's SOPs. 

    ASSESSMENT CRITERION 6 
    The reasons why the inner wall of a hydrosphere's shell must be thoroughly examined before a new bladder is fitted, is explained in terms of the importance of locating and treating any corrosion that may be present. 

    SPECIFIC OUTCOME 7 
    Complete all necessary documentation. 
    OUTCOME RANGE 
    Includes but is not limited to:
  • Importance of documentation, completion of servicing job card, impact of incorrect data. 

  • ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The necessity of noting all the materials used and the time involved in the maintenance of pressure vessels is explained with respect to allocating the costs for the service. 

    ASSESSMENT CRITERION 2 
    The completion of the job card at the end of the service is demonstrated in accordance with the company's SOPs. 

    ASSESSMENT CRITERION 3 
    The consequences of incomplete documentation are explained in terms of the impact this will have on the finances and stock replenishment for the business/company. 


    UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
  • Anyone assessing a learner against this unit standard must be registered as an assessor with the relevant ETQA.
  • Any institution offering learning that will enable achievement of this unit standard must be accredited as a provider through the relevant ETQA.
  • Moderation of assessment will be overseen by the relevant ETQA according to the moderation guidelines in the relevant qualification and the agreed ETQA procedures. 

  • UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
    N/A 

    UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    The learner is able to identify and solve problems in which responses display that responsible decisions using critical and creative thinking have been made by:
  • Applying safety precautions when transporting and handling pre-charged pressure vessels. 

  • UNIT STANDARD CCFO WORKING 
    The learner is able to work effectively with others as a member of a team, group, organisation or communities by:
  • Participating with others in the installation of pressure vessels. 

  • UNIT STANDARD CCFO ORGANISING 
    The learner is able to organise and manage oneself and one's activities responsibly and effectively by:
  • Coordinating the phasing and timing of the installation and commissioning of a pressure vessel with that of the pump installation. 

  • UNIT STANDARD CCFO COLLECTING 
    The learner is able to collect, organise and critically evaluate information by:
  • Locate the pump performance data and compare this with the pressure vessel's maximum pressure rating to decide whether to fit a pressure relief valve. 

  • UNIT STANDARD CCFO COMMUNICATING 
    The learner is able to communicate effectively using visual, mathematical and/or language skills in the modes of oral and/or written presentation by:
  • Relaying information of the pre-charge pressure settings to the client for maintenance inspections. 

  • UNIT STANDARD CCFO SCIENCE 
    The learner is able to use science and technology effectively and critically, showing responsibility towards the environment and health of others by:
  • Understanding the relationship that the compressibility of the gas in a pressure vessel has on the stored energy in the vessel. 

  • UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    REREGISTRATION HISTORY 
    As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015. 

    UNIT STANDARD NOTES 
    The Learner:
  • Is expected to perform the specific outcomes reflected in this unit standard without direct supervision.
  • Should have access to work site procedures.
  • Should demonstrate an application of ethics and values.
  • Must apply basic principles of general safety and customer care.
  • Should demonstrate an awareness of the expectations and obligations of basic employee/employer relations including industrial relations principles.

    At this level the communication/reporting of issues arising in the workplace, is embedded in the Specific Outcomes and the related Assessment Criteria.

    It is understood that, due to the nature of the work environment and the skills level of the Learner, that the aspects of teamwork form an integral part of the necessary Specific Outcomes and related Assessment Criteria.

    The points included under the notes, should be included when the qualifying Learners are being assessed. 

  • QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Elective  73109   National Certificate: Landscape Irrigation  Level 3  NQF Level 03  Reregistered  2023-06-30  AgriSETA 


    PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD: 
    This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.
     
    NONE 



    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.