Unit of competency details

CPCPRF4011B - Design and size roof drainage systems (Release 1)


Usage recommendation:
Is superseded by and equivalent to CPCPRF4011 - Design and size roof drainage systemsSupersedes and is equivalent to CPCPRF4011B Design and size roof drainage systems. 26/Nov/2020
Supersedes and is equivalent to CPCPRF4011A - Design and size roof drainage systemsMinor changes throughout the unit Equivalent to CPCPRF4011A 06/Feb/2013

Release Status:
ReleaseRelease date
1 1 (this release) 07/Feb/2013


SchemeCodeClassification value
ASCED Module/Unit of Competency Field of Education Identifier 040327 Plumbing  

Classification history

SchemeCodeClassification valueStart dateEnd date
ASCED Module/Unit of Competency Field of Education Identifier 040327 Plumbing  07/Aug/2013 
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Modification History

Minor changes throughout the unit

Equivalent to CPCPRF4011A

Unit Descriptor

This unit of competency specifies the outcomes required to design, size and document the layout of components of roof drainage systems.

Application of the Unit

Site location for work application will be residential and commercial, and may be a new work site or an existing structure being renovated, extended, restored or maintained.

Licensing/Regulatory Information

In some jurisdictions, this unit of competency may form part of accreditation, licensing, legislative, regulatory or certification requirements.



Employability Skills Information

This unit contains employability skills.

Elements and Performance Criteria Pre-Content

Elements describe the essential outcomes of a unit of competency.

Performance criteria describe the required performance needed to demonstrate achievement of the element. Where bold italicised  text is used, further information is detailed in the required skills and knowledge and/or the range statement. Assessment of performance is to be consistent with the evidence guide.

Elements and Performance Criteria


Prepare for planning. 


Nature and scope of planning task are identified and confirmed.


Work health and safety  (WHS) and environmental requirements  associated with planning, sizing and documenting the layout of roof drainage systems are adhered to throughout the work.


Work is organised and sequenced in conjunction with others involved in or affected by the work.


Tools and equipment  required for planning, sizing and documenting the layout of roof drainage systems, including personal protective equipment, are selected and checked for serviceability.


Work area in which planning process is to be conducted is prepared.


Identify system requirements. 


Information  and specifications for the required work are obtained and confirmed, if necessary by site inspection.


Regulations and Australian standards relevant to the work are consulted and applied to all aspects of the work, including statutory and regulatory authorities’  requirements.


Roof catchment areas and design flows are determined from rainfall data and relevant Australian standards.


Quantity and size of gutters, sumps, rain heads and downpipes are determined according to relevant Australian standards, plans and specifications.


Plan system layout. 


Layout of roof drainage system is planned according to development plans, specifications, relevant Australian standards and workplace procedures.


Required materials  and components of roof drainage system  are specified and optimised according to relevant Australian standards from the proposed design.


Plans are recorded according to regulatory authorities' and workplace requirements.


Sustainability principles and concepts  are observed when preparing for and undertaking work process.


Restore work area. 


Work area is restored according to workplace procedures.


Tools and equipment used in the process are refurbished and left according to workplace procedures.


Documentation is completed according to workplace requirements.

Required Skills and Knowledge

This section describes the skills and knowledge required for this unit.

Required skills 

  • communication skills to:
  • access information
  • enable clear and direct communication, using questioning to identify and confirm requirements, share information, listen and understand
  • follow instructions
  • identify requirements
  • use language and concepts appropriate to cultural differences
  • use and interpret non-verbal communication, such as hand signals
  • literacy skills to:
  • complete workplace documentation
  • read and interpret:
  • documentation from a variety of sources
  • regulations, relevant Australian standards, plans, specifications and drawings
  • record plans
  • identifying and accurately reporting to appropriate personnel any faults in tools, equipment or materials
  • numeracy skills to apply measurements and calculations
  • planning and organising skills to:
  • plan and sequence tasks with others
  • plan and set out work
  • teamwork skills to work with others to action tasks and relate to people from a range of cultural and ethnic backgrounds and with varying physical and mental abilities
  • technology skills to:
  • access and understand site-specific instructions in a variety of media
  • use mobile communication technology

Required knowledge 

  • accessing relevant information sources for the work activity and the processes for the calculation of catchment areas and design flows
  • capacity of fabrication machinery involved in the production of roof draining components
  • Australian standards applicable to roof drainage
  • capillary action, thermal expansion and fabrication techniques to prevent leaking
  • characteristics of various metals and finishes
  • computers and computer-aided design (CAD) software
  • corrosion prevention treatment requirements of cut sheets
  • design concepts and performance measures for various roof draining components for all types of roofs
  • electrolysis and problems associated with the use of dissimilar metals
  • implications of climate variations for the design of roof draining components
  • job safety analysis (JSA) and safe work method statements (SWMS)
  • levelling and alignment processes
  • process of planning, sizing and documenting the layout of roof drainage systems
  • relevant statutory requirements related to planning, sizing and documenting the layout of roof drainage systems
  • SI system of measurements
  • workplace and equipment safety requirements

Evidence Guide

The evidence guide provides advice on assessment and must be read in conjunction with the performance criteria, required skills and knowledge, range statement and the Assessment Guidelines for the Training Package.

Overview of assessment 

This unit of competency could be assessed in the workplace or a close simulation of the workplace environment providing that simulated or project-based assessment techniques fully replicate plumbing and services workplace conditions, materials, activities, responsibilities and procedures.

Critical aspects for assessment and evidence required to demonstrate competency in this unit 

A person who demonstrates competency in this unit must be able to provide evidence of:

  • locating, interpreting and applying relevant information, Australian standards and specifications to the planning, sizing and layout of roof drainage systems
  • applying safety requirements throughout the work sequence, including electrical safety requirements and the use of personal protective clothing and equipment
  • as a minimum, the ability to design, size and document the layout of a roof drainage system for three varied roof types, including at least one type incorporating eaves gutter and one type for a commercial building incorporating box gutters, sumps or rain heads, ensuring:
  • application of sustainability principles and concepts
  • correct identification of details of the plan
  • correct selection and use of appropriate processes, tools and equipment
  • completion of all work to specification
  • compliance with regulations, relevant Australian standards and organisational quality procedures and processes
  • communicating and working effectively and safely with others.

Context of and specific resources for assessment 

This competency is to be assessed using standard and authorised work practices, safety requirements and environmental constraints.

Assessment of essential underpinning knowledge will usually be conducted in an off-site context.

Assessment is to comply with relevant regulatory or Australian standards’ requirements.

Resource implications for assessment include:

  • an induction procedure and requirement
  • realistic tasks or simulated tasks covering the minimum task requirements
  • relevant specifications and work instructions
  • tools and equipment appropriate to applying safe work practices
  • support materials appropriate to activity
  • workplace instructions relating to safe working practices and addressing hazards and emergencies
  • material safety data sheets
  • research resources, including industry-related systems information.

Reasonable adjustments for people with disabilities must be made to assessment processes where required. This could include access to modified equipment and other physical resources, and the provision of appropriate assessment support.

Method of assessment 

Assessment methods must:

  • satisfy the endorsed Assessment Guidelines of the Construction, Plumbing and Services Training Package
  • include direct observation of tasks in real or simulated work conditions, with questioning to confirm the ability to consistently identify and correctly interpret the essential underpinning knowledge required for practical application
  • reinforce the integration of employability skills with workplace tasks and job roles
  • confirm that competency is verified and able to be transferred to other circumstances and environments.

Validity and sufficiency of evidence requires that:

  • competency will need to be demonstrated over a period of time reflecting the scope of the role and the practical requirements of the workplace
  • where the assessment is part of a structured learning experience the evidence collected must relate to a number of performances assessed at different points in time and separated by further learning and practice, with a decision on competency only taken at the point when the assessor has complete confidence in the person's demonstrated ability and applied knowledge
  • all assessment that is part of a structured learning experience must include a combination of direct, indirect and supplementary evidence.

Assessment processes and techniques should as far as is practical take into account the language, literacy and numeracy capacity of the candidate in relation to the competency being assessed.

Supplementary evidence of competency may be obtained from relevant authenticated documentation from third parties, such as existing supervisors, team leaders or specialist training staff.

Range Statement

The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised  wording, if used in the performance criteria, is detailed below. Essential operating conditions that may be present with training and assessment (depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts) may also be included.

Work health and safety  is to be according to commonwealth, state and territory legislation and regulations and may include:

  • handling of materials
  • hazard control
  • personal protective clothing and equipment prescribed under legislation, regulations and workplace policies and practices
  • safe operating procedures, including recognising and preventing hazards associated with:
  • electricity
  • hazardous materials and substances
  • other machines
  • surrounding structure and facilities
  • trip hazards
  • underground services
  • use of tools and equipment
  • work site visitors and the public
  • working at heights
  • working in confined spaces
  • working in proximity to others
  • use of firefighting equipment
  • use of first aid equipment
  • workplace environment and safety.

Environmental requirements  cover water quality management and may include:

  • clean-up protection
  • stormwater protection
  • waste management.

Tools and equipment  may include:

  • computers running appropriate CAD software
  • drawing instruments
  • ladders
  • laser measuring devices
  • measuring equipment.

Information  may include:

  • charts and hand drawings
  • instructions issued by authorised organisational or external personnel
  • job drawings
  • manufacturer specifications and instructions
  • material safety data sheets (MSDS)
  • memos
  • organisation work specifications and requirements
  • plans and sketches
  • regulatory and legislative requirements, particularly those pertaining to:
  • National Construction Code
  • WHS and environmental requirements
  • plumbing regulations
  • relevant Australian standards, including:
  • AS/NZS3500 National plumbing and drainage: Part 3.2 Stormwater drainage
  • SAA and SNZ HB 114:1998 Guidelines for design of eaves and box gutters
  • safe work procedures relating to planning, sizing and documenting the layout of roof drainage systems
  • signage
  • verbal, written and graphical instructions
  • work bulletins
  • work schedules, plans and specifications.

Statutory and regulatory authorities  include:

  • commonwealth, state or territory, and local authorities administering applicable Acts, regulations and codes of practice.

Materials  for design of roof drainage systems may include:

  • drafting and drawing materials
  • plans and specifications
  • manufacturer catalogues and specifications.

Components of roof drainage system  may include:

  • downpipes
  • gutters
  • rain heads
  • sumps.

Sustainability principles and concepts :

  • cover the current and future social, economic and environmental use of resources
  • may include:
  • efficient design principles are used throughout to minimal environmental impact
  • efficient use of material are incorporated in the design including recycling of material
  • rainwater harvesting concepts are applied
  • efficient energy usage
  • disposing of waste material to ensure minimal environmental impact.

Unit Sector(s)

Functional area 

Unit sector 

Plumbing and services

Custom Content Section

Not applicable.