Shower floors that dont make the grade

There are many cases - especially in building renovations where inexperienced contractors lay tiles on a flat surface.

Australian Standard AS 3740 – 2004 Waterproofing of wet areas within residential buildings, Appendix C, states that, “The recommended ratio of fall within a shower area is between 1:60 and 1:80”.

Constuction of your shower floor with appropriate fall toward the waste outlet will ensure that your shower is not turned into a "mini swimming pool".

In instances such as pictured above, the contractor was found to be unqualified. Demolition of the tile floor revealed that the substrate waterproofing was also sub-standard. The tiling in both ensuite and bathroom will need to be stripped and redone. Estimated cost: $10,000.

PVC pipe and stress fracture

PVC pipes and fittings must be installed with provision for movement and expansion.

This fracture in a PVC sweep junction is within an inaccessible first floor space of a three storey commercial building. We located the defect during a process of litigation.

Plumbing Inspectors visit to the Werribee Sewerage Pumping Station

Readers might be interested in these images - Melbourne Water Plumbing Inspectors visiting the Werribee Sewerage Pumping Station - 1991.

Maintenance for temperature control devices in Australia

Thermostatic mixing valves, tempering valves and end-of-line temperature actuated devices should be regularly tested to ensure that they are operating in accordance with Australian Standards and manufacturers requirements.

Many plumbers are not aware that there is an Australian Standard that specifies the testing of both thermostatic mixing valves and tempering valves at intervals not exceeding 12 months. Also, where required, end-of-line temperature actuated devices should be tested at intervals not exceeding 1 month.

The current standard is AS 4032.3: 2004 Water Supply – Valves for the control of heated water supply temperatures. Part 3 Requirements for field testing, maintenance or replacement of thermostatic mixing valves, tempering valves and end-of-line temperature control devices.

Check with your regulatory authority regarding the application of the Standard and any reporting requirements.

The Australian Standard can be downloaded on-line from SAI Global.

Peter Wenning

Wenning delivers sustainable plumbing solutions

Wenning Technical Services is an environmental plumbing consulting business specialising in water, wastewater and solar hot water. We meet and exceed client expectations with sustainable plumbing solutions. This is achieved by analysing the current and future needs of the client, bringing experience and technical expertise to develop solutions that are:

• Socially and environmentally responsible
• Financially beneficial
• Low maintenance and durable
• Adaptable and flexible

Two Sample Projects

KCC Park – Skye

Six years ago, the Victorian Canine Association (VCA) Office relocated from the Royal Melbourne Showgrounds to KCC Park, a 30 hectare site on the Westernport Highway, Skye. Water was being delivered to the site by water truck, which was expensive and inefficient.

Various alternative water source options were examined including rainwater harvesting from the main pavilion roof, and bore water. In anticipating a significant increase in public traffic to the site, and also finding that the ground soil had moderate levels of salt and high sodium, there were two important considerations. Firstly, delivery of a predictable safe potable water supply, and secondly reduction of sodium levels to provide better conditions for growth of grasses.

A development plan for KCC Park included full development of the site with new competition, lure racing, lure and herding areas, a dog park and endurance track. Planting of grasses, trees and shrubs would be required, and the salt and sodium levels in the soil would need to be reduced and controlled to enable establishment and growth.

Through project management and negotiations with South East Water, a 150 mm PVC 1.6 kilometre water main extension was constructed and connected to KCC Park. The pipeline was constructed to South East Water and WSAA standards. South East Water then contributed $56,000 (50%) to the construction and then adopted the pipeline as their asset.

Within KCC Park, the old pump system was decommissioned, and the new potable water supply was connected to the existing plumbing.

Three years after completion of this pipeline, thousands of visitors to the site on any weekend have safe potable drinking water. The cost savings are around 80% on delivery of water by truck, and the VCA investment in the project has already been returned in savings. The VCA no longer pumps water and this reduces greenhouse emissions, and maintenance costs.

The VCA has now connected Class A Recycled Water to KCC Park from the Eastern Irrigation Scheme. Low cost, nutrient rich recycled water will be used to further develop the site and enable growth of a variety of grasses and plants. This will also reduce consumption of potable water at the site and assist in achieving the government’s goals of reducing water consumption, and 20% of water recycling by 2010.

Patterson River Secondary College – Patterson Lakes

Patterson River Secondary College has a playing field with a dry hard surface in need of an effective irrigation solution.

A solution was needed that would pay for an irrigation system, save water and educate students on the social responsibility and benefits of saving water. An examination of funding opportunities produced the solution.

It was decided to apply for a Community Water Grant. The water savings and community benefits of our project would need to be identified to satisfy the grant criteria. Two areas were identified.

The first area was installation of a water efficient irrigation system for the playing field. Four manually placed hose and sprinkler systems were being used to water the fields and this was ineffective and inefficient. A new automatic system watering at night would reduce evaporation and optimise water penetration to the grass root zone improving the playing field surface.

The second area was in outcomes arising from education of students on the social responsibility and benefits of saving water. A building upgrade (already funded) would replace existing inefficient plumbing with WELS compliant 4.5/3 litre dual flush cisterns and tapware, saving a significant volume of water. The benefits of the building upgrade and new irrigation system would be measured by installing sub water meters.

It was estimated that the water use in the toilet areas will be reduced by around 50% (approx 25% of the total water use). This would be measured through meter readings before and after the new building upgrade, and this project information will be published and imparted to students.

For this project, we applied for and received a $31,000 Federal Government Community Water Grant from the $2 billion Australian Government Water Fund.

Patterson River Secondary College will now have a playing field with an improved surface, safer for student sports. The new irrigation system on the playing field will save water and require less labour. Also, the students will learn the benefits and social responsibility of saving water while enjoying their new building upgrade.

These water efficient projects were successful because the outcomes were;

Socially and environmentally responsible
Financially beneficial
Low maintenance and durable
Adaptable and flexible

Peter Wenning is a Hydraulic Services (Plumbing) Consultant based in Melbourne. He can be contacted via email pwenning@bigpond.com

References:

http://www.topaq.com.au
http://www.communitywatergrants.gov.au

A fraction too much friction

Friction is the resistance a surface meets in moving over another. We rely on it when we apply the brake in a car, or hold a hot cup of coffee.

Friction is an important consideration in plumbing design. For large projects, the plumbing hydraulic consultant needs to allow for frictional losses in the design of services such as water, gas, heating and ventilation.

For small projects, plumbers also need to understand the effects of friction. Proper sizing of pipes and ducts, secure pipe clipping and protection against abrasion all contribute to the performance and durability of plumbing.

Here we look at some plumbing problems where the consumer was rubbed up the wrong way…


Heating ducts drive you around the bend

Recently, we inspected three new 2 storey townhouses in a row, south of Melbourne, each with a ducted central heating unit installed in the first floor ceiling. Unfortunately, there was very little air from some outlets, particularly at ground floor ceilings. One heating unit was shutting down regularly via the safety high temperature cut-out switch.

Inspection of the controls and gas supply revealed that they were adequate. The central heating units had sufficient capacity to heat the townhouses. The units were rated at 20 kW and given the size of the internal areas, could deliver 45 W/m³, and this would have been satisfactory for these particular buildings.

We found that all three systems had poor air distribution. The air velocity at some ground floor outlets was 0.4 to 0.5 m/s at around 48 deg C. The supply air temperatures should have been in the range of 55 to 62 Deg C, and outlet neck velocities should have been in the range of 1.5 to 2.5 m/s.

The gas-heating units were designed to deliver around 620 litres per second of supply air for 11 outlets. Thus the design supply air quantity per outlet was 56 L/s. The measured quantities per outlet averaged only 15 L/s. We also measured the return airflows to verify the air quantities, and ensure that the supply air was not disappearing somewhere.

Generally, the flexible ducting in the ceiling spaces had excessive lengths and abrupt bends, and this caused poor airflows at affected outlets. Poor air distribution (ductwork, grills etc) can also cause poor airflows at air outlets. Poor airflows can cause high delivery temperatures, and in fact caused one gas heater to shut down regularly via the safety high temperature cut-out switch.

While the duct sizes appeared adequate, we found that the air supply outlets were slightly undersized. Each air outlet had a 150 mm neck diameter. Outlets of this size should be limited to airflows of around 40 litres per second.

It is vital for plumbers to fully consider the airflow friction losses and air velocity in flexible heating ducts especially to the furthermost outlets through proper duct sizing and reducing excessive lengths and abrupt bends.

Equally important is designing a balanced duct configuration so that outlets close to the heater don’t have excessive air velocities. High air velocity through ducts and outlets causes air friction noise, and this is undesirable, particularly in bedrooms.

Pipe abrasion

Excessive friction, particularly on water pipes, can cause abrasion resulting in burst pipes and property damage.

Case 1

Pipe hammer can cause friction and abrasion when a valve closes rapidly and there is pipe movement.

Early this year, we investigated the cause of water damage to a hospital in Melbourne. The water damage included wet area floor and plaster wall; and adjacent office timber floor and carpet.

A flexible stainless steel braided hose water connection to a basin had burst. Each time the hot water flick mix tap was operated, the stainless steel braided hose would move and rub against an edge of the porcelain basin causing the stainless steel braiding to fray and hose to burst. This flexible connection had been installed for 7 years.

Flexible stainless steel braided hose connectors are approved for use in Victoria, but are never clipped. Australian Standard AS/NZS 3500.4: 2003, Section 4.5 states that,” Water services installed above ground shall be retained in position by brackets, clips or hangers” and, “Brackets, clips and hangers shall be clamped securely to prevent movement, unless designed to allow for thermal movement”.

It’s unlikely that these flexible connectors will ever be clipped properly, but highlighting the potential problem might prevent a reoccurrence.

Case 2

Excessive friction can cause pipe stress fracture when there is lack of provision for pipe lagging / wrapping.

Late in 2005, we were called to inspect a fracture in a cold water supply pipe. The pipe passed through a brick wall and was connected to a hot water unit. With minor settlement of the hot water unit, the pipe was pulled down on the brick wall causing a pipe fracture.

The pipe had not been wrapped with lagging through the brickwork. In this case, if the piping had been lagged through the brickwork, the piping would have been free to move with low friction and the fracture would not have occurred. As in the previous case, the plumbing was only 7 years old.

AS/NZS 3500.1: 2003 requires that pipes through masonry or concrete be lagged or wrapped with an impermeable flexible material. Unfortunately, there are few inspections to pick-up these defects in workmanship, and property owners are left with the defects and resultant water damage.

Summing up

Friction is a broad subject, and perhaps a little off the wall. Nevertheless, it is a relevant and important consideration in many facets of plumbing design and installation.

Peter Wenning is a Melbourne based plumbing consultant. He can be contacted at pwenning@bigpond.com