3.4 The case studies
Sub-district hospital - Waitakere Hospital
Summary
|
Client |
Waitemata District Health Board |
|---|---|
|
Site address |
Lincoln Road, Henderson, Auckland |
|
Total floor area |
14,700m2 |
|
Cost/m2 |
$2435 (adjusted to 2005) |
|
Conventional cost/m2 |
$2400 (1.5% below project cost) |
|
Contract value |
$35 million |
Economics
The indicative economics for this case study building are set out in the table below. Adding sustainable building strategies was initially seen as too expensive, but a subsequent feasibility study and loan funded by the Energy Efficiency and Conservation Authority (EECA) under its design energy audit and Crown loan scheme proved otherwise. A grant was also received from Infrastructure Auckland for the stormwater measures included in the project (not accounted for in the table below).
View the indicative economics for this case study building (large table).
Due to their intensive use and highly serviced nature, hospitals can be excellent examples of sustainable building.
Environmental summary
Site:
- Courtyard building forms for natural light and ventilation.
- Culturally inclusive and barrier-free facilities.
- Stormwater retention and filtration integrated as water treatment.
Material:
- Simple, cost-effective measures were included.
Waste:
- Re-use of existing buildings, and waste strategies were adopted during construction and are being implemented in operation.
Client brief
The Waitemata District Health Board and Waitakere City Council worked in partnership with the community to ensure that the hospital fitted with Waitakere City's Eco City vision.
Facilities
The two-level hospital block comprises:
- the ground floor with three medical/surgical wards (70 beds), including six-bed coronary care unit; four operating theatres; new radiology/imaging department; emergency department/acute assessment unit and a cafeteria
- the lower ground floor with two assessment, treatment and rehabilitation wards (51 beds); occupational therapy/physiotherapy; kitchen facilities; hospital support services; cultural health facility and home health services.
Site
The site development included partial refurbishment of existing buildings and the construction of new facilities. Courtyards were created in the middle of the building to bring sun, light and air into the interior and provide green space for the occupants. A landscaped stormwater retention and treatment pond provides a public amenity for the site.
Concept
As part of the project development, a series of design principles was created, underpinning the design direction. These included:
- putting the patients and their families at the centre of the design process
- designing for energy efficiency
- being environmentally friendly, which included avoiding waste, safe disposal of hazardous goods
- recycling as much material as possible
- maximising the use of natural lighting
- specifying the use of sustainable and environmentally friendly materials
- reducing and controlling stormwater runoff and wastewater, providing quality stormwater treatment and reusing waste.
Site plan
Energy
Energy-savings options were modelled and tested to identify their cost benefits. The first was for the partial recirculation of air using an economiser cycle. This improves the efficiency of the system by using outside air for cooling when conditions permit.
High-efficiency lighting was used, which included:
- tailoring lighting levels to each individual space
- increasing the level of localised switching and using luminaires fitted with low loss ballasts
- fitting high-frequency dimmable ballasts to selected areas (such as corridors and courtyards) to allow daylight to complement artificial lighting
- installing occupancy sensors in partially occupied areas such as toilets and storerooms, ensuring lighting is used only during occupied periods.
The levels of insulation were increased from code levels, with R 2.0 insulation in the walls and R 3.5 in the ceiling. Natural ventilation was provided to the assessment, treatment and rehabilitation (AT&R) wards and to cultural health.The pump and fan energy use has been reduced by the use of low-pressure loss systems and high-efficiency motors.The building management system (BMS) controls all systems serving the hospital in an energy-efficient way, based on time of day, outside weather conditions, internal conditions and the presence of people. It also provides an energy management tool to ensure energy use can be monitored.The table below shows the economics for the energy savings measures that formed the basis of the Crown loan application. Taking into account the capital costs saving for adopting natural ventilation, the capital cost premium fell to $50,000 and the payback period to 0.33 years.
Energy savings measures
View energy saving measures (large table).
Hospital foyer
Water
Stormwater from the hospital flows into a landscaped stormwater pond before flowing into nearby Henderson Creek. The car park stormwater flows into swales and rain gardens and then flows into the same creek. This cleanses the water of sediment and pollutants and also prevents flooding downstream.
Swales: Stormwater from the new car park and access road at the back of the hospital site runs off into the swales. About 450m of lineal swales were installed to cope with approximately 3400m2 (30% of the paved area on the site) of road area.
Two sand filters: These have been fitted next to the new main car park to help treat the existing 300 car park spaces.Rain gardens: Installed at the end of the swales, these naturally filter run-off from the car parks before the water enters the stormwater system. Stormwater treatment pond: This 1900m2 pond treats the stormwater to 75% efficiency. It treats stormwater from an 18 ha catchment area. Rainwater tanks: Six 250m3 tanks collect rainwater run-off from the main hospital roof, with the water used mainly for toilet flushing and cooling tower make-up. Estimated savings from reusing this water equate to annual water consumptions bills being reduced by $15,000 per annum, a significant saving given that during 2005 water costs in Auckland increased from $1/m3 to $4.50/m3.
On-site green tanks
Waste minimisation
Wherever possible, existing hospital elements have been re-used, upgraded and integrated in the new community hospital, with about 50% of the hospital being retained and progressively upgraded.
No formal system of waste management was established, but the contractor was well organised and minimised the amount of prefabrication, re-work and waste disposal.
The hospital is moving towards establishing a formal waste management system like the one being implemented by Wellington Hospital. Clinical waste costs about 25 times more to dispose of than general waste - and up to 75% of the materials disposed of as clinical waste are actually general waste. The waste management system will include:
- implementing systems for refuse collection, including general and clinical waste which require incineration
- educating staff to help them understand the environmental impact of waste generation and how personal actions can reduce waste impact
- working with suppliers to minimise the use of non-recyclable or non-biodegradable packaging
- recycling systems for ease of segregation and staff use.
As identified at Wellington Hospital, quick gains can be made by addressing specific items such as gloves, IV bags and nappies.
Site
Existing buildings were re-used and refurbished. Stormwater retention and treatment ponds serve as a public amenity. Swales and rain gardens are used to deal with run-off from car parks.
Public access has been improved and made easier with a barrier-free philosophy.
Transport
Waitakere residents previously had to travel to the North Shore for accident and emergency facilities. The new hospital in West Auckland reduces car trips significantly. A new traffic light interchange at the hospital entry improves traffic flows and safety.
Materials
The choice of materials and their environmental effects were considered, but the lack of a direct return on investment and higher cost made uptake limited. Some specific measures showing a positive return on investment were adopted.
- The building generally uses relatively simple, low-cost materials, simple pitched/barrel-vaulted roofs and avoids use of high-tech cladding solutions. Instead walls use a robust, vandal-proof base and lightweight, highly insulated top portion.
- A post-tensioned ground floor slab was used. This was cheaper, quicker and more structurally efficient and used less material. This approach is widely used in Australia but less so in New Zealand.
- Polypropylene hot and cold pipework systems were used instead of traditional pipework. This material was initially questioned by facilities management, but a demonstration and testing convinced them it should be included.
- The mixed use of fibreglass and polyester insulation provided the optimum solution to insulation materials use. Fibreglass was used in encapsulated locations and polyester in exposed locations.
- Chillers use no ozone-depleting refrigerants.
- The air diffuser design was chosen to minimise cleaning requirements.
- Art was placed and integrated in all areas of the hospital, acknowledging the role of the environment in aiding recovery and wellness.
- The hospital is moving towards a gluteraldehyde-free operation.
Process
A master plan was first developed by the hospital general manager, with the hospital's Orion Programme management team, Di Carlo Potts Architects, project managers Carson Group, quantity surveyors Rider Hunt and Maunsell Consultants. Hospital staff then put together a brief for each department and a business plan was put to the government. Other consultants were brought into the process, including services engineers and energy modellers Connell Mott MacDonald, civil engineer Harrison Grierson and structural engineer Buller George. An advisory group including Waitakere City Council, the Energy Efficiency and Conservation Authority (EECA) and Robert Vale from Uniservices stimulated interest in the development of an 'Eco Hospital'. A cost/benefit analysis of energy and water savings, funded by EECA's Design Audit Scheme, was carried out by Connell Mott MacDonald. This justified contributions and loans from EECA and Infrastructure Auckland, and meant the project was the first to benefit from EECA funding for both a design audit and Crown Loan.
Lessons learnt
Unfortunately, with no detailed design brief available at the start of the design process, no clear objectives were set for energy saving and no benchmarks were made. This will make judging the success of the energy-efficient design very difficult. Robert Vale (a sustainable building consultant on the design team) recommends the following process for future projects:
- construct the design brief after key stakeholders have identified key issues
- strike up partnerships with outside companies or organisations for sources of funding
- draw up the brief in collaboration with both specialist consultants and key stakeholders, before design consultants are engaged
- establish checkpoints to review whether design objectives have been reached
- use energy modelling and life-cycle costing on systems and construction to identify real opportunities for cost-effective design.
Credits
Client: Waitemata District Health Board
Project manager: Carson Group
Architects: Di Carlo Potts Architects (Sydney)
Quantity surveyors: Rider Hunt
Services engineers and energy consultant: Connel Mott MacDonald
Civil engineer: Harrison Grierson
Structural engineer: Buller George
Sustainable design consultant: Robert Vale, Waitakere City Council Sustainable Design Advisor
