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Introduction

The installation of a Photovoltaic Panel System on a roof covered with prime COLORPLUS® or ZincAL® minimises the impact of air pollution on our environment and utilises the natural resources thereby reducing the impact of our carbon taxation. To ensure the integrated PV Panel System and Roofing maintains its weather tightness and durability , guidelines to installation and maintenance becomes a requirement.

a. Integrated Project Construction Assembly

The metal roof durability is impacted by both the PV Panel System and Roofing Assembly , therefore

both should be considered during design process , installation and maintenance routines.

1. Roofing Assembly The durability of the profiled roof sheeting , considered as an unwashed area sheltered from normal rainfall , would be impacted by a list of factors , below are the major considerations : - Roof Slope

The lower the roof slope the greater is the opportunity for moisture and dirt to be entrapped for longer time periods.

- Roof Surface A profiled sheet with a rough surface will have a tendency to withhold a higher degree of dirt and/or moisture , latter will be aggravated by a low roof slope.

- Purlin Spacing To ensure the roofing assembly performs over the lifespan of the project it would be advised that load calculations are performed at design phase. Since inadequate installation can lead to water ponding phenomena.

- Profile Type The lifespan of the integrated construction assembly will be enhanced by the use of an appropriate concealed fix , as it requires no protrusions into the roof sheeting, this reduce the risk of other corrosion types. Refer to Solar Panel Bulletin v1 for corrosion types

Photovoltaic Panels (PV) Guidelines To Good Practice on a Metal Roof

Technical Article TA 01 Rev 0 - 30 July 2019

Figure1 . Typical examples of framed PV panel mounted on metal roofing

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Fig 2. Typical Pierced Fix Installation Fig 3. Typical Concealed Fix Installation

The pierced fix installation , utilises the exposed fasteners , latter can contribute to the the entrapment of moisture , debris and leaves

2. Photovoltaic Panels ( PV Panels) Assembly The PV Panel assembly requires reasonable consideration when it comes to managing its influence on the durability and water tightness of a project roof with COLORPLUS ® or ZincAL®. Main considerations regarding PV Panel assembly are listed below..

- PV Panel Composition Fig 4 . Typical PV Panel Assembly

The main considerations in Fig 4 would be the following : Frame : The advanced AZ coated Alloy used with the ZincAL® product is more compatible with the oxides produce by any compatible Aluminium frame, however any other compatible component not enhancing corrosion on the roof sheeting can be considered. Glass : It would be advised to use low iron , alkali free and lead free glass , with an anti reflective coating not containing titanium oxide and zinc oxide.

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- PV Panel Assembly Design

* Bracket Design and Composition The clamped type , composed of compatible Aluminium would be preferred, since the AZ coating is composed of 80% by volume aluminium, however any other bi metallic compatible can be considered. Fig 5 The clamp type preferred

Fig 6 The pierced fix type not recommended

* Clearance of the PV Panel from the roof sheeting surface The designed clearance should accommodate the following …

1. Sufficient access for cleaning , maintenance and inspections.

2. Free air flow , ensuring quick drying for areas beneath the PV Panel.

3. Self Cleaning , ensuring no build up of debris , entrapped moisture or or other contaminants.

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* PV Panel Slope Design It would be advised that a PV panel design considers a possible slope , since latter ensures a rapid run down of natural rainfall , condensation and water (during the required maintenance washdowns). Further it promotes an easy drying of the roof sheeting and minimise accumulation of contaminants. The introduction of the sloped PV panels has maintenance and reduction on the impact on the roof sheeting advantages Fig 7 Typical sloped PV Panels

The use of a flat PV panel structure , relevant to the roof sheeting , can be enhanced by considering a roof slope. Fig 8 Typical sloped roof with PV Panels

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3. PV Panel Installation Practices

- Sealants to be used should be neutral in composition.

- Any dissimilar metals , such as lead, brass , copper and stainless steel should Not be used in direct contact with COLORPLUS® and ZincAL®.

- The use of timber in direct contact with COLORPLUS® and ZincAL® should be avoided

as other corrosions type can be introduced , refer to Solar Panel Bulletin v1.

- Swaffing created during installation should be immediately be removed.

- Electrical cables not be placed directly on the roof sheeting and result in any accumulation of debris or other contaminants.

- The earthing of the PV panel installation should be approved by an authorised engineer.

b. Project Maintenance The PV Panel installation , unwashed area sheltered from normal rainfall , has to be maintained to ensure the project installed with COLORPLUS® or ZincAL® offers the

weather tightness and durability over the lifespan of the project.

1. Maintenance During Installation

• PV Panel Installation practices needs to ensure that during installation any damages to the COLORPLUS® and ZincAL® be corrected , accordingly.

• Swaffing and any other debris to be cleaned off immediately.

• Compatible Walk ways be installed , ensuring no damage or abrasion to the roof sheeting surface, occurs.

• PV Panel arrangement should allow for easy access , maintenance and inspection.

Fig 9 Typical High Installation Activity

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Fig 10 Typical high Installation Activity

2. Maintenance over the Project Lifespan Current PV Panel designs require a frequent maintenance schedule , ranging from 3 to 4 time with a calendar year. Latter is required to ensure the efficiency of the PV Panel installation. It is therefore required that the contaminants washed from the PV Panels also be removed from the roof sheeting , ensuring the contaminants below the PV Panel Is adequately removed.

Fig 11 Ease of cleaning a sloped PV Panel

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Fig 12 Impact on Roof sheeting when cleaning a PV Panel Fig 13 The need for correct walk ways and PV Panel Arrangement

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Fig 14 Typical walk ways and ease of access

Summarised Maintenance Integrated Project Assembly

Typical information is supplied is this article , any project specific requirements needs to be discussed with Safal Steel prior to installation