Copper or Plastic Piping: Which is best

Copper Piping

Water Piping – Copper or Plastic

When it comes to water pipes, copper has been the material of choice for a very very long time.

Plastic pipes of all sorts (PEX, uPVC, HDPE) have become increasingly popular in the past 20 to 30 years. One reason being the increasing cost of copper pipes over their equivalent in plastic.

So, what are the pros and cons?


There is no one 100% safe solution. Little is known at present about the plastic piping release of volatile organic compounds (VOC’s) and assimlable organic carbon (AOC’s). Copper is the system with the easiest of issues to control and mitigate and on balance appears to be the better option. 

Mitigating Potential Terrorist Attacks on Buildings

Murrah Federal Building, Oklahoma City, USA.

Terrorism is not an easy or pleasant topic of discussion, but in this day and age, it is a reality that we need to be prepared for, rather than experience the consequences.

As building professionals, it is incumbent upon all of us to at least address the issue when we are engaged in our normal daily design processes. As we hear on the news daily, the enemy is getting more sophisticated with brains running their ill quests for the destruction of humanity. We need to be aware of our own vulnerabilities and potential risk.

There are rules we follow in relation to minimum distance between building fresh air intakes from toilet exhausts, sanitary vent pipes and other sources of objectionable odours. Thanks to dilution, these are not typically life threatening.

But, what if a terrorist released poisonous or radioactive gas into the fresh air intake of a large iconic building with large occupant densities? How safe are these fresh air intakes? Are they secure? Can they be quickly evacuated if detected?

Whilst New Zealand may seem removed from this, we are not immune. As some say ‘An ounce of prevention is worth a pound of cure.’

It is worthy to note that existing buildings with fresh air intakes that are impractical to secure can be protected. This includes the installation of sensor array, capable within milliseconds of detecting chemical, biological and radioactive acts of terrorism. The sensor array can immediately shut down the building ventilation system and sound the fire alarm to evacuate the building.

The above is only one scenario that we need to be considering.

The US Department of Homeland Security has a reference manual to Mitigate Potential Terrorist Attacks Against Buildings. We can assure you this manual is an eye opener and a must read.

Download it here:

Cooling and Heating by Chilled Beams are Here to Stay

Chilled Beams 20141126

Chilled beams is the world’s most recent technique for in-ceiling heating and cooling applications.

Simply based on a horizontal air coil with room air induced over it by a combination of buoyancy and induction air forces, the system’s benefits are;

  • A virtually silent system,
  • No moving parts, no fans,
  • No routine maintenance within the office space,
  • Low ceiling space requirement (about 220 mm),
  • Can be either exposed or ceiling concealed,
  • Most efficient system available,
  • No condensate drainage,
  • Very good zone control capability,
  • Can be installed in a raking ceiling.
  • Can easily substitute conventional 2 or 4 pipe chilled water systems in existing buildings and
  • Now chilled beams are fabricated in New Zealand.

Pacific Consultants (now known as MEPS Building Engineers) have to date completed two projects incorporating chilled beams;

  • Recently, the new Mainfreight Terminal building and offices in Christchurch and
  • The Willis Centre, Wellington. (Merit Award- ACENZ Innovate Awards of Excellence)

Natural Green Pools!

Green Pools

Natural Green Pools is a new trend in the domestic swimming pool industry. Hopefully not due to the dreaded common algae (Pediastrum boryanum).

Whilst a private pool is an asset and a pleasure for the family, many people suffer from allergic reactions to chlorine, normally added to swimming pools as a disinfecting agent.

If you are intending on designing a new pool for your family or for a client, why not consider a natural green pool.

Admittedly, this is not a new idea.

Based on a chemical free natural filtration system, it allows the perimeter water-loving plant beds to act as a water filter and do all the work a typical pool filter would do.

Pool water overflows onto the perimeter plant beds (water restoration area). Water is filtered by absorption through the carefully designed plant bed. Pumped underdrains (acting as subsoil drainage coils but in reverse) the clean and filtered water is then returned to the pool. Simple, no chemicals added!

So, your next natural green pool will require no harmful chemicals, will be fairly low-tech, and once established, it will require little of your time to maintain. Only top up now and then whilst you are drinking a cold minty mojito. Oh, these summer days are coming!

Warranty Conditions of Contract for Fixtures Fittings & Equipment

Pacific Islands

Pacific Consultants (now known as MEPS Building Engineers) are involved in a small number of South Pacific design building projects. Recently we ran into an issue with the warranty conditions of contract for equipment repair during the normal warranty period.

The manufacturer of the equipment had warrantied the equipment for replacement parts only but tagged out time and travel knowing the final destination for the equipment.

The contractor expected the manufacturer to travel to the island and repair the equipment for free.

The situation remained unclear for a few months regarding who was responsible for the repair. It was not until we managed to sight the original sale offer that the situation became clear.

The lesson learned is: whilst most contract documents are implicit on warranties, it pays to stipulate the warranty conditions of contract for replacement parts, travel to site and labour.

LED: Lighting for the Future

2014 LED Lighting

LED lighting technology is fast approaching maturity. We are at a stage where we now specify LED lighting as a matter of course for certain applications.

Today, LED lighting can deliver colour temperatures ranging between 2700K (warm white) to 4000K (cool white) that maintain a very high colour rendering quality that are similar to fluorescent lamps.

Lighting efficiency:  LED light sources  beats all other light sources hands down. Simple comparison courtesy of the European Commission is shown below.

Pricing of LED lamps and fittings have come down substantially. For example at present prices, an LED downlight retails at around $50 compared to $25 per halogen recessed down light. Still double in price but once thermal stability, heat shielding and energy costs are taken into account, overall costs can be demonstrated to be similar at day one and much less in the long run.

2014 LED Lighting Chart

Services Must be Seismically Restrained to Comply with Clause B1 of the NZ Building Code

Seismic Map of NZ

Whilst the seismic restraining of building services is nothing new to the industry, the recent earthquakes in Canterbury have generated new emphasis on the design and installation of seismic restraints in buildings.

The standard that we all have to comply with is NZS 4219:2009. The following are an example of the requirements and stipulations contained within;

Ceiling Supported Equipment

Equipment Within Ceiling Voids: Air diffusers, grilles, and other fittings weighing less than 10 kgs shall be positively fixed to the ceiling. Equipment exceeding 10 kgs in weight must be independently supported of the building structure plus a 25 mm gap between component and ceiling to allow independent movement. Equipment weighing greater than 25 kgs will require specific restraint design.

Light Fittings

Recessed or surface mounted luminaires must be positively fixed to the ceiling T-rail system by way of nuts, bolts or locking clamping devices.

Cable Trays

Cable trays suspended greater than 400 mm from structural support must be seismically restrained. For cable trays not requiring restraint must be installed with a clearance of 150 mm from hangers and braces. Where a cable enters the building, it must be sleeved to allow 25 mm movement is all directions.

Electrical Cabinets

Must have doors fitted with top and bottom catches. Electrical components contained within cabinets must have straps, bars, bolts or similar to provide positive restraint.


Generally pipes less than 50 mm in diameter require no specific seismic design. Similarly, pipes rigidly supported no more than 150 mm from the structure above require no additional support. Pipes that require no seismic support will have to be installed 150 mm from adjacent ceiling hangers, braces and other separately supported equipment. Pipes larger than 200 mm in diameter will be subject to specific seismic support design.

Air Ducts

Rigid ducting with a hanger length greater than 200 mm between the structural support and top of the duct shall require seismic restraint. Interestingly, the Standard stipulates flexible ducts longer than 1.5 m also requiring seismic restraint.

Fans, Fancoil Units etc

Suspended components that are installed in line with duct systems and weigh more than 10 kgs will require to be supported and laterally braced independently of the duct system.


Such as concrete plinths supporting equipment must be reinforced and anchored to the structural slab they are mounted to.

Vibration isolators and resilient mountings

Shall have stoppers or snubbers in each orthogonal horizontal direction and vertical restraint to resist overturning.  Snubbers shall be specifically designed to restrain the seismic forces imposed by the dynamic impact of the component against the snubber.

Tanks and Vessels

Have to be considered as a single mass and restrained against sliding and turning.

Flues and Stacks

Have to be restrained in two perpendicular horizontal directions. Supports shall also be designed to prevent slip joints and other flexible connections from being pulled apart. Flues shall be accessible along their entire length for inspection.

Lifts and Escalators

Refer to NZS 4332:1997 Non-domestic passenger and goods lifts.

Fire Sprinkler Pipework

Refer to NZS 4541:2007 Automatic fire sprinkler systems.

Whilst the above is a condensed summary of Standard 4219:2009, please take the time to refer to it here for additional information and requirements.

Domestic Hot Water Systems to Comply with H1, NZ Building Code

2014 Domestic Hot Water Systems

Tips and Tricks: No. 2, Domestic Hot Water Systems

Generally design professionals, in dealing with the NZBC clause H1, address issues relating to building thermal insulation.

Additionally, H1 also addresses issues of ventilation, lighting design and domestic hot water generation.

A pertinent aspect is the restriction imposed on the length of hot water piping between a domestic kitchen sink and the hot water unit.

This stipulation translates to a maximum total pipe length of 7m for a 20mm diameter pipe (the equivalent of 2 litres of water).

Further information on Clause H1 is available here.

Carpark Ventilation Systems


When designing for a mechanical ventilation system, engineers follow the requirements of the NZ Building Code which stipulates AS1668 as an acceptable solution. AS1668 dictates the use of supply or extract air ducting or both with stringent requirements on the placement of supply and extract air grilles to achieve compliance often based on extract rates of 3.0 litres/s/m2 of car park area.

An alternative solution lies with NZS4303. Whilst the ventilation rate is double at 7.5 litres/s/m2, the use of ductwork, supply and extract air grilles is not mandatory. This approach yields a simple solution of a number of plate type extract fans fixed to the car park external walls strategically located to ensure a good “sweep” of the car park floor with fresh air. The absence of ductwork provides for an economic, uncomplicated and simple design with maximum available floor to ceiling heights.