THE OFFICIAL JOURNAL OF AIRAH Ecolibrium · 2016-09-17 · 8.Debate over healthy building materials...

EcolibriumTHE OFFICIAL JOURNAL OF AIRAH MAY 2016 · VOLUME 15.4

Doing WELLMaking buildings better for people. PRINT POST APPROVAL NUMBER PP352532/00001

ECOLI BR I U M • MAY 201674

F E A T U R E

In 1982, futurist John Naisbitt introduced “Megatrends,” i.e., large-scale trends building on such immutable facts as the unprecedented number of Baby Boomers born in the two decades after World War II.2 In 2007, Patricia Aburdene updated the concept in her book Megatrends 2010: The rise of conscious capitalism, with its focus on the growing interest in corporate social responsibility, a trend clearly driving sustainability thinking and green building forward.

What megatrends currently affect green buildings? In this chapter, you’ll learn about 10 megatrends that will shape and drive green building technologies, markets, government

rules and certification systems through 2020 and beyond.

A megatrend’s strength is that we can’t wish it away; it’s here to stay and the key issue is how to build on it. In technology, the turn to mobile computing after the introduction of the iPhone in 2007 and the iPad in 20104 is clearly such a trend, one that building owners and green building proponents increasingly must deal with.

Globally, green building will likely continue its growth, especially considering green building’s rapid uptake in countries in the Asia-Pacific region, South America and the Middle East. Each year, more government agencies,

universities, property developers and corporate real estate managers incorporate green design ideas and measures into their buildings and facilities, and there is nothing on the horizon that will stop this megatrend.

The top 10 megatrends affecting green buildings:

1. Green building certification’s growth rate is flat in the United States.

2. Energy efficiency leads the way.

3. Zero net energy buildings (ZNEBs) are on the rise.

4. Competition among rating systems will increase.

5. A sharper focus on existing buildings will emerge.

6. Cloud computing and Big Data analytics will provide much needed direction.

7. Cities and states will demand building performance disclosure.

8. Debate over healthy building materials will become even more vexatious.

9. Solar power will finally break through.

10. Expect a heightened emphasis on water conservation.

The future of green building:top 10 megatrendsThe excerpt is taken from Chapter 2, Reinventing Green Building: Why Certification Systems Aren’t Working and What We Can Do About It by Jerry Yudelson, New Society Publishers, May 2016, and is reprinted here with permission. In this chapter Yudelson charts what he sees as the 10 major megatrends impacting green buildings.

Zero Net Energy at the Olver Transit Center, Greenfield, MA. Powered by a 98 kW PV array, geothermal heat pumps and a wood pellet boiler, this 2,230 sq m transit center in western Massachusetts operates on only 101 kWh/sq m/year.⁷ Serving 70 occupants and 100 visitors per day and completed in 2012, it is an early example of zero net energy architecture in a difficult climate. Image credit: John Linden

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Note that five of these 10 megatrends revolve around energy: energy efficiency, zero net energy, cloud-based (and data-driven) energy management, energy performance disclosure and solar power. This focus is largely driven by two practical considerations: first, for most buildings, energy is the largest uncontrollable operating cost; and second, growing understanding about the connection between building energy use and global climate change means that corporate social responsibility and government action are also key drivers for improving building energy efficiency.

Although green building originally focused on the “triple bottom line” (energy; economy, environment and equity; social well-being), concern for energy issues increasingly is driving corporate and governmental interest in green building.

MEGATREND #1: Green Building certification’s growth rate Is flat in the United StatesGreen building in North America, Europe, the Middle East and Asia-Pacific will continue to grow, but at a slower rate, as more building owners come to accept the business case, especially in larger office buildings, corporate real estate, high-end universities and state and federal government buildings. The discussion following Table 4.1 estimates that green building project registrations accounted for about

15 per cent of total new construction project area in the United States during 2014.

In contrast to the new construction market, the 2014 tally of 17 million sq m in existing building certifications (Table 4.1) represents only 0.2 per cent of existing US commercial building area. At the end of 2015, the US total for LEED certifications is still quite low – about 3.8 per cent of commercial buildings’ total.

Slower growth in green building certification in new construction doesn’t mean that designers are ignoring important elements of sustainable design, but this book’s thesis is that without major changes certification in the United States will show no growth, with important implications both for certification organisations and for sustainability in the built environment.

MEGATREND #2: Energy efficiency leads the wayBeginning in 2012, energy-efficiency green building retrofits have shown stronger growth than energy-efficient new construction. This trend is strongest in corporate and commercial real estate, along with “MUSH” market (Municipal, University, School and Hospital) projects. In the MUSH market, cheap capital and financing from ESCOs – Energy Service Companies – drive building owners to “sell” most future energy savings in exchange for investors providing an upgraded or modernised physical plant. (The federal government equivalent, Energy Service Performance Contracts, chose 16 national vendors in 2012 to provide projects worth $85 billion to government agencies.) In The World’s Greenest Buildings: Promise vs. Performance in Sustainable Design, I make a case that absolute building performance, with resultant lower operating costs (vs. the currently more common “relative improvement” approach), should be the primary focus for green building if we want to rapidly cut carbon emissions.

There are huge opportunities in energy efficiency and most are concentrated in 25 per cent of the building stock, as shown in Figure C.15. A more cost-effective approach to certifying existing buildings should first make use of the

concentrated nature of these efficiency opportunities by launching a rating system tailored for such buildings and their key performance indicators (Chapters 14 and 15 provide a more extended discussion of this opportunity).

MEGATREND #3: Zero net energy buildings are on the riseZero net energy buildings are increasingly commonplace (Figure 2.1). A 2014 survey by the New Buildings Institute (NBI) identified more than 160 ZNEBs in the United States, with an additional 53 low-energy buildings that were “zero net energy capable.” Commercial real estate developers (and in some places, new home developers) have also begun to showcase zero net energy designs to differentiate their projects, as have some developers wanting to upgrade older

MEGATREND #4: Competition among rating systems will increaseIn US new construction ratings, LEED may see enhanced competition from Green Globes and possibly from new entrants in specialised niches, e.g., retail or office interiors. (See discussion in Chapter 12.) In 2013 and 2014, the federal government put both LEED and Green Globes on an equal footing for government projects, lending further legitimacy to Green Globes. Other North American systems (Figure 2.2) include LEED Canada; BOMA BEST (from BOMA Canada), which is focused on the existing building market; the Living Building Challenge; and BREEAM.

In Europe, the BREEAM rating system is aggressively marketing itself, particularly in Western Europe, where it competes with country-specific systems such as HQE in France and DGNB in Germany and Austria. In all, BREEAM International is marketing the system in nearly 60 countries and may even enter the US market should the USGBC’s new LEEDv4 falter; BREEAM International has already entered the market in Mexico.

In Asia-Pacific, a more likely scenario is for country-specific rating systems to be dominant, especially in more established markets such as Australia, Singapore, Japan, India and China.

I became

interested in

long-term trends

because an

invention has

to make sense in

the world in which

it is finished, not

the world in which

it is started.

– Ray Kurzweil


F E A T U R E

In Canada, LEED Canada competes in the existing buildings market with BOMA Canada’s BOMA BEST rating system.

MEGATREND #5: A sharper focus on existing buildings will emergeBeginning with the Global Financial Crisis (or Great Recession in the United States) in 2008–2010, the green building industry began to switch from evaluating new building projects to assessing existing buildings and tenant spaces. This trend crested in 2009 (Figure 8.8), but it could re-emerge for two reasons. First, third-party green building project registrations for new construction peaked during 2012–2014 and is now a steady 2000–2500 projects per year in the United States, representing annually about 25 million sq m of new building construction.

With annual new construction registrations for LEED essentially flat, the existing building market may get greater attention, particularly with energy efficiency retrofits and a renewed focus on using the Energy Star system. But LEED may not benefit from this trend. LEED certification is not as

newsworthy as it once was and LEED existing building certifications accounted for fewer than 545 buildings in 2014 and 584 in 2015, in each year representing about 0.01 per cent (that’s not a typo!) of the total US nonresidential building stock of 5.5 million buildings.

MEGATREND #6: Cloud computing and Big Data Analytics will provide much needed directionBuilding owners and third-party service companies increasingly manage larger buildings remotely, using software platforms that provide performance monitoring, data analytics, visualisation, fault detection and diagnostics, portfolio energy management and text messaging, all using the cloud. Since 2012, this trend has been reflected in many new offerings in building automation, facility management, wireless controls and building services information management. Related trends include energy dashboards, cheap sensors, a greater awareness of the business case for energy upgrades and more government regulation and actions to cut energy use.

MEGATREND #7: Cities and states will demand building performance disclosureSince the 2007 adoption of the Architecture 2030 standard (encouraging all existing buildings to cut energy use 50 per cent and all new buildings to be “zero net energy” by 2030) and the introduction of the first “2030 District” in Seattle in 2010, group efforts to cut carbon emissions and encourage voluntary performance transparency are a major trend in the United States, capitalising on concerns over climate change and incorporating values of openness and transparency embraced by many larger businesses and government agencies. By mid-2015, 10 US cities had functioning 2030 districts.

This trend is highlighted by more than 30 large and medium-sized US cities requiring (i.e., going beyond “encouraging”) commercial building owners to disclose green building performance to tenants and buyers and, in some places, to the public. This trend will spread rapidly as an easy way to monitor reductions in carbon emissions from commercial and governmental buildings and to put pressure on owners to invest in energy efficiency retrofits and renovations.

Since 2010 the European Union has mandated performance disclosure, for both new and existing buildings, under the Energy Performance in Buildings Directive (EPBD). Typically, a buyer or lessee or renter gets the disclosure form during a transaction. (Figure 2.3 shows a typical example for a new building of an Energy Performance Certificate, or EPC, from the UK.) The EPC is often shown as a relative scale (similar to Energy Star) so full performance disclosure expressed as energy use intensity (EUI, recorded either in Btu/sq. ft. or kWh/m2) still lags. There are also Display Energy Certificates (DECs) for existing buildings, but their uptake is not widespread at this time.

Energy Performance Certificates and Display Energy Certificates show both projected/current performance and the potential for improvement, including both energy use and carbon emissions. In Australia, disclosing a building’s NABERS energy rating system became mandatory in commercial real estate

Figure 2.2: North American Green Building certification systems.

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transactions after 2010.

MEGATREND #8: Debate over healthy building materials will become even more vexatiousThere is little doubt that debates about healthy building products and their documentation, such as Environmental Product Declarations (EPDs), Health Product Declarations (HPDs) and various

“Red Lists” of chemicals of concern that designers should avoid, will doubtless grow larger, more frequent and more contentious. The problem with EPDs and HPDs is that there are few accepted national consensus standards for determining the information that should be in an EPD or HPD, and how that information should be verified.

Nonetheless, it’s easy to predict that building product manufacturers will try harder to compete for market share based on disclosure of chemicals of concern. A June 2015 report found

1,852 HPDs available from 698 brands. It’s also easy to foresee that industry developed disclosure systems will compete with “verified” EPDs offered by independent rating organisations. This could lead to massive market confusion for product specifiers who must choose between proven products that they know from experience are appropriate for a given use and newer products that claim to be healthier because they meet various criteria from healthy product rating organisations, but which may not be as suitable for the intended use or as cost-effective as established products.

MEGATREND #9: Solar power will finally break throughSolar use in buildings will continue to grow, primarily because many US states will implement aggressive Renewable Portfolio Standards (RPS), while the country as a whole moves (slowly) toward zero net energy buildings. In mid-2015, 37 of 50 US states, including California, New York and Texas, had some form of RPS, mandating a specific percentage contribution from renewables to electricity supply.17 California’s RPS is the most aggressive, mandating by 2020 a one-third renewables contribution.

In the United States, most electric utilities would rather build and control large central solar power plants than lose revenues to tens or even hundreds of thousands of systems feeding solar power into “their” grid. The persistence of low interest rates makes financing capital-intensive solar energy systems much easier, especially in combination with requirements in many states that electric utilities implement “net metering” programs. Such programs pay a building owner for surplus electricity produced at the same rate as power purchased from the local utility.

In the future solar power undoubtedly will be our primary electricity source, but the question is when. One expert argues convincingly that Moore’s Law applies to solar power; this only makes sense, because solar modules are based on semiconductor technology. So the time may come sooner than anyone expects!

Figure 2.3: UK energy performance certificate.


F E A T U R E

Solar power has one advantage over other forms of energy efficiency: It is highly visible. Photovoltaics on the roof of a building demonstrate to employees, customers and the public that a firm or institution is committed to renewable energy and a greener future.

New tools will help drive more building owners to using solar power: Google’s new Project Sunroof, announced in August 2015, allows anyone to readily assess whether covering a rooftop with photovoltaics (PVs) would result in energy-cost savings, by combining aerial 3D models from Google Maps, historical weather data, utility prices and local financial incentives.20 A similar system, Mapdwell, spun out in 2015 from an MIT research project, began offering solar prospecting services in New York and San Francisco. Mapdwell shows that each city offers multiple gigawatts of solar production potential.

Solar electricity is likely to reach grid parity in the United States within the next five years, by 2020 or 2021. One estimate predicts, “If solar electricity continues its current learning rate, by the time solar capacity triples to 600 GW (by 2020 or 2021, as a rough estimate) we should see unsubsidised solar prices at about 4.5 cents/kWh for very sunny places, ranging up to 6.5 cents/kWh for more moderately sunny areas.”

In June 2015, Bloomberg New Energy Finance (BNEF) predicted that solar power costs would fall another 50 per cent and solar investment would total $3.7 trillion in the next 25 years; of this growth, 60 per cent would go to rooftop and decentralised systems and 40 per cent to centralised solar power stations. BNEF also expects investment in other renewables such as wind power to total an additional $4.3 trillion.

Solar power growth is the only megatrend that is truly revolutionary, global in scope and likely to radically alter how buildings are designed, built and operated in the next ten years.

MEGATREND #10: Expect a heightened emphasis on water conservationGlobal awareness of the coming crisis in fresh water supply in many regions will increase as global climate change continues to affect rainfall and water

supply systems worldwide. The 2012–2015 drought in California, with more than 70 per cent of the state in extreme drought by summer 2015, brought water concerns to national attention in a way seldom before seen

Owing to heightened concern about future droughts’ impact on water supply and cost for buildings, many building designers, owners and managers aim to further reduce water consumption in buildings by using more water-conserving fixtures, installing rainwater and graywater recovery systems, planting native and adapted vegetation instead of lawns or ornamentals, investing in more efficient cooling towers and other innovative approaches to reducing onsite water use. Case studies in my book Dry Run: Preventing the Next Urban Water Crisis show how this is done in countries such as Germany and Australia as well as in seven major regions of the United States.

SUMMARYThese ten megatrends will continue to drive growth of low-carbon green buildings, adoption of renewable energy in buildings and waterconserving architectural designs throughout the next ten years. We will discuss later in the book why I believe that some megatrends – a strong focus on energy efficiency, renewable energy use (mostly solar power for buildings) and water conservation – should form

the core of new green building rating and certification systems. ❚

Jerry Yudelson, PE, LEED Fellow,istheauthorof13full-lengthprofessionalandtradebooksongreenbuildings,integrateddesign,greenhomes,waterconservation,buildingperformanceandsustainabledevelopment.Dubbed“TheGodfatherofGreen”byWiredMagazine,hispassionforoptimisingthebuiltenvironmentisreflectedbyhismanyyearsofprofessionalexperienceinthegreenbuildingandcertificationfields,servingasanelectedLEEDFellowandaspresidentoftheGreenBuildingInitiative.JerryalsoservedonthenationalboardoftheUSGBCandchairedtheSteeringCommitteeforthelargestgreenbuildingshow,Greenbuild,from2004–2009.HispreviousbooksincludeDryRun,ChoosingGreenandGreenBuildingAtoZ.

This article is extracted from Yudelson’s new book, Reinventing Green Building: Why Certification Systems Aren’t Cutting Enough Carbon and What We Can Do About It. (New Society Publishers, May 2016). Available for 20 per cent pre-order discount at www.newsociety.com/contact/form/92826.

Jerry Yudelson, PE, LEED Fellow.

AIRAH technical publications Purchase online at www.airah.org.au

Consult the cornerstoneConsult the DA manual

The Design Application (DA) series of publications produced by

AIRAH are best-practice guidelines to assist HVAC&R practitioners

with their day-to-day tasks in the design, operation and

maintenance of mechanical building services.

APPLICATION MANUAL

CENTRIFUGAL PUMPSDA01

THE AUSTRALIAN INSTITUTE OF REFRIGERATION, AIR CONDITIONING AND HEATING

APPLICATION MANUAL

DA11


STEAM AND CONDENSATE

APPLICATION MANUAL

NOISE CONTROLDA02


APPLICATION MANUAL

DA03


DUCT WORK FOR AIR CONDITIONING

APPLICATION MANUAL

DA08


HVAC&R AN INTRODUCTION

APPLICATION MANUAL

AIR CONDITIONING LOAD ESTIMATIONDA09


APPLICATION MANUAL

WATER TREATMENTDA18


APPLICATION MANUAL

DA13


FANS

APPLICATION MANUAL

DA15


AIR FILTERS

APPLICATION MANUAL

AIR CONDITIONING WATER PIPINGDA16


APPLICATION MANUAL

DA17

THE AUSTR ALIAN INSTITUTE OF REFRIGER ATION, AIR CONDITIONING AND HEATING

COOLING TOWERS

APPLICATION MANUAL


BUILDING COMMISSIONINGDA27

APPLICATION MANUAL

DA20


HUMID TROPICAL AIR CONDITIONING

APPLICATION MANUAL

DA21


AMMONIA REFRIGERATION

APPLICATION MANUAL

DA21


AMMONIA REFRIGERATION

APPLICATION MANUAL

DA24


WATER SYSTEM BALANCING

APPLICATION MANUAL

DA26


INDOOR AIR QUALITY

DA01 CENTRIFUGAL PUMPS CENTRIFUGAL PUMPS DA01

••• 60

••• 61

• Isolate the pump from the structural loads of the pipework system.

• Compensate for small deviations in alignment between the pump and pipework connection.

• Compensate for expansion and contraction of the pipework or pump due to temperature changes.

9.4.6. Base mounted pumpsThe pump should be correctly levelled before securing to a stable base. Pumps should be well secured to the base in accordance with the manufacturers installation instructions and so that vibration transmission is minimised. Common installation methods used include:

• Grouting the pump to a concrete foundation of suitable mass.

• Using a flexible pad (neoprene, silicone or similar) between the full contact surface of the pump and the foundation.

• Using a base isolation system such as rubber pads or inertia base with spring.

Pumps should not be mounted directly on to springs as this provides no inertia to reduce vibration of the pumps and will impart all vibration to pipework. If pumps are in a noise critical area such as on a suspended floor or roof above or below an inhabited area then inertia bases should be used.

Precision grouting is probably the most critical part of the installation. The surface beneath the base plate must be properly prepared for grouting, any concrete laitance (structurally weak layer) must be removed from the concrete and the aggregate exposed. All dirt and dust must be removed from the area prior to grouting. Properly grouting the base plate to the concrete slab lowers the natural frequency of the base plate and reduces resonant vibrations which can damage bearings and seals.

In all cases the method of isolation should be appropriate for the environmental conditions in service, including temperature, humidity and chemical degradation. Install the pump on the level base and make sure all mounting bolts are centred. Ensure that the pump is level and if not level shim the feet to level the shaft.

Long coupled type pumps will require realignment on site after installation and after any motor replacement. Install the motor on the base and, using a straight edge, perform a preliminary shaft alignment. Shim the motor feet for the

final alignment and align using a laser based system. This should normally be carried out by the pump manufacturer or supplier, and must be completed prior to running the pump.

Modern equipment using laser alignment technology should be used where possible, especially for larger units. The advantages of high precision alignment include less noise and vibration, longer equipment life (bearings and drive components) and less energy wastage at the drive. Aligned pumps can be doweled to the base to prevent future misalignment.

Coordination of condensate trays and drains with pump mounts and inertia bases is an important aspect to consider for chilled water pumps.

9.4.7. In-line pumpsVery small in-line pumps (such as in-line canned rotor pumps) can be supported by the system piping but larger pumps need to be independently supported. Many in-line pumps are configured to make it easy to provide the additional support directly under the pump.

9.4.8. PipeworkThe piping installer should route the piping with flexibility designed into it, using the minimum amount of pipe, fittings, and expansion loops.

Pipework should be independently supported to ensure that no forces or moments due to pipe weights or thermal expansion will be imposed on the pump. Flexible connectors are never designed to carry loads. Similarly pump flanges and connections are not designed to carry the weight of system pipework and liquids. All pipework and accessories should be supported independently of the pump.

During the course of physical routing of any piping system, the installer should ensure the provision of high-point vent and low-point drain connections for the filling and draining of the piping system with water (for hydrostatic testing and operation) and for the purging of air entrapped within the system.

9.4.9. ValvesImproper application and placement of valves in the piping system can be detrimental to system function and can result in malfunction of the valve and in water

Pump

Baseisolation

Pumpisolation

Figure 9.1: Base mounted pumps

hammer. The following precautions should be taken during installation:

• Valves should be installed with the spindles between the vertically upward and horizontal positions, to prevent the entrainment of air and debris in the valve.

• Valves in acid and caustic services should be located below the plant operator’s eye level or in such a manner as to not present a safety hazard.

• The location of valves, with consideration for operating accessibility, should be accomplished in the natural routing of the system from point to point.

• Valves in overhead piping with their spindles in the near horizontal position should be located so that the bottom of the hand wheel is no more than 2m above the floor. Only infrequently operated valves should be located above this elevation.

• A minimum 100 mm of knuckle clearance should be provided around all valve hand wheels.

• Valves should never be installed with the spindle facing downwards.

• Space should be provided for the removal of all valve internals.

9.4.10. InsulationThe piping installer should be familiar with the installation and engineering of the thermal insulation materials specified and specifically with the method of fixing appropriate for the type and thickness of insulation. There must be spacing and clearance between the insulation of one pipe and any adjacent pipe and insulation, or other

possible interference such as structural steel. The piping installer should also recognise that in some applications insulation may not be required for the prevention of heat transfer but will be needed for personnel protection.

Note: Levels of piping insulation, required by regulation (NCC), have been increased over historical practice and designers/installers must allow sufficient clearance to accommodate this.

9.4.11. WiringAll pumps and associated electrical equipment should be wired in accordance with AS/NZS 3000. Control and monitoring instrumentation should be wired in accordance with the manufacturer instructions and all relevant regulations.

Note: Refer AIRAH DA 27 for further information on the installation of control wiring.

9.4.12. AccessThe provision of adequate access to the pump and its accessories for maintenance and service is essential and is a requirement of AS/NZS 3666.1 which is a regulated requirement in Australia through building and health regulations. Large centrifugal pumps are often supplied with access points.

For larger pumps, the provision of lifting eyes and overhead lifting beams or davits should be considered to facilitate pump replacement or servicing in a safe manner.

Figure 9.2: Supporting pipework independently of pump connections

APPLICATION MANUAL

CENTRIFUGAL PUMPSDA01THE AUSTRALIAN INSTITUTE OF REFRIGERATION, AIR CONDITIONING AND HEATING

DA13

FANS

••• 12

Axial fans generate swirl in the discharge airstream and the

removal of the swirl improves fan efficiency. Swirl can be

reduced by using guide vanes, see Clause 2.6.3, or by using

twin impellers independently driven in opposite directions

within the same casing, known as contra rotating see

Clause 2.6.6.Some axial fans are reversible, i.e. they can operate in the both

the forward and reverse directions, often with a performance

reduction when in reverse. In all variations from the standard

configuration the efficiency is lower and noise levels are

generally increased, see Clause 2.6.5

Axial fans can overload at high pressure when they reach

shut off pressure, the peak on the pressure curve for axial

fans. At lower pressures axial fans can also go into stall

which occurs at the stall dip point. At this point the fan

becomes unstable and mechanical failure can occur,

further information on this is provided in Section 5. Axial

fans generally rotate faster than centrifugals to achieve

the same airflow and they tend to generate more noise,

particularly in the higher frequencies, which can be easier

to attenuate than the low frequencies generated by

centrifugals. Axial fans deliver more air at zero pressure

than a centrifugal fan, of the same size and running at the

same speed, but the centrifugal fan will develop more

pressure. A significant feature of axial fans is their lower

costs when compared to other types of fans.

2.6.1. Plate mounted fans

Plate mounted fans, also called propeller fans, are basically an

axial flow impeller running in a square or round plate suitable

for wall, ceiling or panel mounting (i.e. installation category A).

Because of the air entry conditions they develop less

pressure than an axial flow fan of the same size and speed.

Applications include moving air through a partition from

one open space to another and they are also widely

used in heat exchange systems in HVAC&R and industrial

applications (e.g. condensers). These fans can move

large volumes of air but only generate low pressures, see

Figure 2.10. Complex blade designs can be incorporated

to address noise and performance. The design of the

orifice the impeller is mounted in can greatly affect the

efficiencies and noise generated by these fans. Plate

mounted fans can have an adjustable pitch impeller.

Performance depends on where the fan is mounted with

respect to the plate.2.6.2. Tube axial

In its simplest form a single axial impeller is direct-driven by

a motor mounted within a cylindrical frame, (i.e. installation

category D). The fans (also called ducted propeller fans)

move large volumes of air but only generate small

pressures, see Figure 2.11.

Figure 2.10: Typical characteristics of a plate mounted fan

1

2

3

32

1

1 Projecting onsuction side

2 Aligned onsuction side

3 Immersed onsuction side

Volume �ow rate (q)

E�ciency

Pressure

Stat

ic pr

essu

re

E�cie

ncy

Typical performance

Typical configuration

Figure 2.11: Typical configuration of an axial fan unit

Air�ow

(a) Tube axial

(b) Vane axial

Air�ow

Guide Vanes

FANS

DA13

••• 7

2.1. Section Introduction

Fans are made up of three main components:

• Impeller – centrifugal (backward, forward and radial

designs), axial (fixed and pitched), mixed-flow, and

cross-flow designs are used.

• Housing – volutes, diffusers, as well as product casings

and boxes are used.

• Motor – alternating current (AC), direct current (DC)

and electronically commutated (EC) motors are used.

In its most fundamental form a ‘fan’ is made up of an

impeller rotating with or without a casing. When a motor

is added the combination is more accurately called a

‘fan unit’. When the fan unit is installed within a HVAC&R

product the combination is then more accurately called

a ‘fan product’. For simplicity, and in line with common

usage within the HVAC&R community, the term ‘fan’ as

used in this application manual, can also include a fan unit

and a fan product.

This section provides an overview of fan types, motor

types and fan accessories, including their application and

effect on system performance. The first part of the fan

story is to look at how a fan works.

2.2. Standard fan

installation categories

Four generic installation categories are defined in ISO 5801

and fan performance tests are typically performed for one

or more of these installation categories.

They are:1. Category A installations — Open inlet and open outlet

(i.e. no ducting).

2. Category B installations — Open inlet and ducted

outlet.3. Category C installations — Ducted inlet and open

outlet.4. Category D installations — Ducted inlet and ducted

outlet.Fans incorporated into products that are mounted in

a manner that does not reflect any of the standard

categories (e.g. roof-mounted exhaust fans or AHU fans)

are likely to have altered performance characteristics.

2.3. How a fan works

A fan is a rotating bladed machine which continuously

supplies energy to the air or gas passing through it. There

are three main components in a fan, the impeller which is

sometimes referred to as the wheel or rotor, the means of

rotating it, the motor, and the casing or volute, in which

the impeller is contained, if one is used. Some fan types

do not include casings but may include a rotating diffuser

that aids air separation from the blades converting velocity

pressure to static pressure.

Energy is transferred to the air by rotation of the impeller

which may be of the centrifugal, axial, mixed-flow or cross-

flow type. In centrifugal fan types it is the centrifugal force

generated by the mass of air contained within the impeller

at any one instance, as well as the force exerted by the

Fans, an overview

2

Figure 2.1: Standard fan installation categories

Category A – Open inlet and outlet

(ie. no ducting)

Fan

Fan

Category B – Open inlet and ducted outlet

Fan

Fan

Category C – Ducted inlet and open outletFan

Category D – Ducted inlet and Ducted outlet

Fan

APPLICATION MANUAL

DA13


FANS

DA19 HVAC&R MAINTENANCE Application Manual

Application Manual HVAC&R MAINTENANCE DA19

••• 14

••• 15

• Maintainability of the system and future

maintenance strategy,• Location of and safe access to the services,

• Reliable and appropriate control systems,

• Monitoring, metering and recording facilities,

• Certification of commissioning data and results,

• Operating and maintenance information for system,

• Detailed maintenance schedules and instructions,

• Recommendations on maintenance management.

Designers are best positioned to develop the design/

maintenance philosophy for a building or system.Designers have a legal responsibility to ensure that their

design will be safe to operate and maintain. This design

responsibility continues through the construction process

either by the original designers or by subsequent designers

if further design, or modification to the original design, is

undertaken.Designers have a responsibility to inform their clients of

the ongoing maintenance or life cycle costs of their design

proposals and of the future responsibilities of system

owners and operators with regard to maintenance.

Particularly with the provisions of the BCA regarding

part I2 on energy efficient installations and part J8 on

access for maintenance, there is now an explicit legislated

responsibility on the system designer to determine the

maintenance regime for the system plant and to design

for adequate access to that plant to allow the required

maintenance to be performed. Even without the provisions

of I2, there would have been a responsibility to ensure that

plant with a designed required performance maintains that

performance.Specific requirements for operating and maintenance

manuals and the transfer of design related HVAC&R

information must be met if the building construction is

under a building rating or accreditation regime. The BCA is

a design and construction document and does not contain

administrative matters such as maintenance manuals

but their need is implicit in order to know what plant is

required to be maintained and when.2.3.4 HVAC&R System contractors

Regular inspections should be made during system

installation by HVAC&R system contractors or their

representatives to ensure:• Adequate and safe access to plant is provided,

• Original specification for materials and equipment is

complied with,• Equipment installation requirements are complied with,

• As installed drawings supplied are accurate,

• Operating and maintenance manuals are complete,

• Commissioning procedures are carried out

appropriately,• The installed system meets the design intent.

Contractors have a responsibility to inform owners of the

ongoing maintenance requirements for the plant and of

the future responsibilities of system owners and operators

with regard to that maintenance.Specific requirements for operating and maintenance

manuals and the transfer of design related HVAC&R

information are required to be met if the building

construction is under a building rating or accreditation

regime. The AIRAH HVAC&R system star rating tool also

contains particular requirements or credits for operating

and maintenance information.2.3.5 System commissionersCorrect commissioning of a system is essential for

optimum system performance and the implementation

of a successful maintenance program. Because the

commissioning data will form the basis of the maintenance

plan, the personnel commissioning the system also have

maintenance responsibilities. Commissioning personnel

should ensure that:• Commissioning procedures for plant and systems are

carried out appropriately,• Commissioning data is properly recorded and logged,

• System commissioning data complies with system

design data,• Any non-compliance is reported and addressed.

Specific requirements for commissioning, commissioning

management and commissioning documentation

are required to be met if the building construction is

under a Green Star accreditation regime. The AIRAH

HVAC&R system star rating tool also contains particular

requirements for commissioning and commissioning

management.Periodic recommissioning of a system or parts of a

system is also required for optimum long term system

performance (refer to Clause 6.2).2.3.6 Building/Facility managersThe building manager, facility manager or maintenance

manager has a significant maintenance responsibility. A

primary role of the manager is to ensure that the building

and its systems are functioning optimally.Managers, as well as driving the maintenance process, also:

• provide the link between system maintainers and

building occupiers,• need to respond to complaints quickly and efficiently,

• ensure the building occupants are satisfied,

• often provide a supervisory role for maintenance staff

and contractors,• maintain documentation such as the asset register and

operating and maintenance manuals,• monitor, meter, record and report system performance,

• communicate maintenance issues,• resolve access issues,

• report on the maintenance effectiveness,

• are responsible for the periodic review of maintenance

plans and procedures.Successful maintenance management relies on the on-

going commitment of managers to maintenance planning,

maintenance funding and user education.2.3.7 Maintenance ContractorThe maintenance contractor needs to supply system

maintenance in accordance with the maintenance

contract.

The maintenance contractor needs to ensure that

maintenance personnel are appropriately trained, skilled

and licensed to carry out the work and are supervised as

appropriate.The maintenance contractor should keep abreast of

developments in all areas and advise the owner when it is

considered that modification can be made to the plant to

economic advantage.Contractors may also have a responsibility for the formal

reporting of ongoing sustainability or performance

indicators associated with particular systems.Modern maintenance is a partnership of stakeholders

and the maintenance contractor needs to ensure that the

knowledge loop, regarding HVAC&R services, between

system maintainers and operators is facilitated.The maintenance contractors’ role can include:

• Inspection, testing and monitoring,• Repair and replacement,• Compliance activities and records,

• Purchase and installation of plant,• Purchase and installation of spares and consumables,

• Control of onsite stores and spares,• Energy management and reporting,

• Water management and reporting,• Supervision and assessments,

• Cost control,• Complaint response and trouble shooting.2.3.8 Maintenance service personnelIt is essential that maintenance service personnel be

appropriately trained, skilled and supervised for the work

undertaken. They need a good understanding of how each

system should operate and in particular fully understand

the control system logic being applied to the system.

Maintenance personnel require a range of certifications

and licences to carry out the required maintenance work

on HVAC&R systems particularly in respect to refrigerant

handling, boiler work, water treatment, hydraulic services

and electrical work.

2.3.9 TenantsTenants need to be instructed in the correct operation of

the system and this should be in lay terms. Tenants need

to be engaged by the building manager on the energy

efficiency/sustainability features of the building systems.

Tenant fit-outs can impact on system performance and

HVAC&R systems may need some redesign as a result of

fit-out activities. Rules or procedures need to be in place to

ensure that any negative impacts of tenant fit-outs on the

overall building and system performance is mitigated.

Tenant systems can be connected to or be separate from

base building systems. They can be complex and require

considerable maintenance in themselves.Tennant systems are also covered by the BCA and building

law. Building laws as well as other laws, do not recognise

any tenant/owner contractual arrangement but generally

make the building owner responsible for compliance.

Tenants and occupiers need to be informed of the

imperatives for maintenance and should be encouraged to

facilitate all reasonable requests for access to HVAC&R plant

for maintenance.

2.3.10 OccupierOccupants need to understand the correct operation of

the system and the influence that their behaviour can have

on system performance.Well informed occupants can alert maintenance managers

to potential problems and also identify opportunities for

future or further system improvements.Occupiers form part of the communications and

knowledge loop between system operation and

maintenance.

Figure 2.4 HVAC&R system knowledge loops2.4 Implications of inadequate maintenanceInadequate maintenance of mechanical plant will result

in unsatisfactory operation, higher costs and unnecessary

unexpected breakdowns.

Owners ManufacturersDesignersInstallers

Regulators:Building& OHS

ManagersOperators MaintainersAuditorsSurveyors

Occupiersand

Tenants

APPLICATION MANUAL

HVAC&R MAINTENANCEDA19


THE OFFICIAL JOURNAL OF AIRAH Ecolibrium · 2016-09-17 · 8.Debate over healthy building materials...

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