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ELECTRICITY SYSTEMS FOR HOSPITALS A tutorial for ensuring safety, reliability and efficiency

Angelo Baggini

March 2011

Electricity is only of third-rate interest to hospitals. Their core business is the welfare of its patients, for which

medical appliances are required, which, on their turn, require electricity. That said, electricity is a vital utility

which malfunctioning or interruption can easily lead to disastrous consequences. This combination - being

absolutely vital but far from the main interest domain of the organization – entails a certain risk.

Standards and regulations prescribe how a hospitals’ electrical installation should be conceived to ensure

safety and reliability. Those regulations are complemented by the prescriptions of the equipment

manufacturers. All those rules, however, create a fairly complex tangle for the user, making it difficult to figure

out which rule has to be applied where and how exactly it has to be implemented. In this tutorial we will try to

shed light on those regulations and give a comprehensive overview.

Once safety and reliability are taken care of, the focus can shift towards energy efficiency. The fact that

efficiency is only of second priority for a hospitals’ electrical installation does not mean its impact cannot be

significant. By focussing on energy efficiency, hospitals can often make surprisingly large savings on the total

cost of ownership (TCO) of their installations. In this paper we will tackle a few major energy efficiency topics

relevant to medical building management.



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I. THE GENERAL ELECTRICAL INSTALLATION

A. SAFETY AND RELIABILITY

1. ENSURING SAFETY: STANDARD IEC 60364-7-710

All low voltage electrical installations have to comply with the general international standard for electrical

safety IEC 60364. Section 710 of this standard is particularly dedicated to medical locations, prescribing some

additional requirements for these premises. It is included in the seventh part of IEC 60364, hence the code IEC

60364-7-710. Most national regulations on electrical safety in medical locations are derived from IEC 60364-7-

710. It applies to hospitals, medical clinics, medical and dental surgeries, rooms for physiotherapy, beauty

centres and veterinary surgeries. The standard also applies to medical rooms integrated into non-medical

buildings, such as industrial premises, offices, or residential buildings. Albeit primarily a safety standard, it also

provides some rules on ensuring availability (see further).

Standard IEC 60364-7-710 classifies all medical rooms into three groups, primarily based on the use of ‘applied

parts’. An ‘applied part’ is any part of an electro-medical device that might come into contact with a patient.

Group 2 includes all rooms where a discontinuity of power supply may endanger the patient’s life. It

also includes all medical locations in which applied parts are used for intra-cardiac procedures (risk on

micro-shock on cardiac muscles). Finally, it includes all rooms related to operations with general

anaesthesia: pre-operation rooms, operating theatres, surgical plaster rooms, and post operation

waking-up rooms.

Group 1 includes all medical locations that don’t belong to group 2 and where applied parts are used,

externally or invasively.

Group 0 includes all medical locations where no applied parts are used, such as outpatient rooms,

massage rooms without electro-medical devices, offices, store rooms, canteens, changing rooms,

corridors, staff hygiene facilities, waiting rooms, etcetera.

Assigning the rooms to one of these three groups must be done by qualified medical personnel. If no such

personnel is available, the national healthcare organisation must be called in.

Often, the function of a room is changed during the lifetime of a hospital, for instance because of changed

needs. It can therefore be wise to equip certain rooms for a higher group than their initial use demands. Those

rooms will then be upgradable without significant costs for the electrical installation.

The IEC standard prescribes the following protective measures for each group:

For group 0, no extra measures have to be taken, additional to the general prescriptions for electrical safety in

buildings (standard IEC 60364).

For groups 1 and 2, additional measures are prescribed for protection against electrocution through direct or

indirect contact with live parts of the system.

‘Direct contact’ means a person touches a live part of the electrical system. ‘Indirect contact’ means a person

touches a conductive (metal) part which is normally not live, but which has become live due to a fault in the

electrical insulation.



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Note that in any case for medical locations:

The protection device should bring the possible contact voltage in case of an incident below 25 V.

(Whereas the maximum contact voltage for non-medical locations is 50 V.)

The type of Residual Current Device (AC, A or B) should be in correspondence with the type of devices

in the network to ensure its well-functioning.

In case a TN earth connection method is used, the TN-S variant should be used downstream of the

main distribution switchboard.

b) PROTECTION TROUGHT MEDICAL IT SYSTEM.

This shall be applied to all circuits in Group 2 medical locations supplying:

Medical equipment located at less than 2.5 meter from the walking surface, or which could enter the

patient’s environment

Socket outlets (except those powering devices of more than 5 kVA and radiological devices)

A Medical IT System guarantees the continuity of power supply to critical medical operations after a first earth

fault, while at the same time ensuring protection against indirect contact. This is made possible thanks to a

medical insulating transformer , which galvanically separates a terminal circuit from the rest of the electrical

system.

Insulation transformers exist with a power of 3.5 kVA, 5 kVA, 7.5 kVA and 10 kVA. As transformers have a long

life span (several decades), it is better to over-estimate the power load to enable future extension without the

need to exchange the transformer. Specifications for the medical insulating transformer are given in standard

IEC 60364-7-710.

Should a second earth fault in another part or device occur, the medical insulation transformer cannot

anymore guarantee the safety and well-functioning of the system. For this reason, the Medical IT System

should contain a device for permanent earth insulation resistance monitoring.

This device will give an alarm (alarm light plus acoustic signal) when a first earth fault occurs, so that the

required measures can be taken to rectify it as soon as possible. The monitoring device itself can be placed

inside the electrical switchboard of the medical IT system (see further), but the acoustic and optical signals

must be placed at a location with continuous presence of qualified healthcare personnel. Specifications for the

insulation monitoring device are given in standard IEC 61557-8.

The medical IT system should be connected to a separate switchboard , or to a separate section in the main

switchboard. It should have an ordinary power supply as well as an emergency power supply (see further). The

switchboard of the medical IT system typically contains: the insulating transformer, an insulating monitoring

device for the 230 V circuit, an insulating monitoring device of the 24 V circuit, a transformer 230/24 V – 1 kVA,

a surge arrester, and a temperature probe PT100.

The circuits of the medical IT system are preferably installed in separate cable ways (pipes, ducts, boxes). In

case ducts or boxes are shared with other circuits, an insulation barrier should be installed between both

circuits. In any case, group 2 medical locations can never contain cable ways supplying power to other

locations. In group 2 medical locations, all conductors should be shielded . Ducts should be protected by

omnipolar automatic miniature circuit breakers. Moreover, circuits of medical IT systems should be protected

with fuses or thermomagnetic automatic miniature circuit breakers.



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c) PROTECTION THROUGH CLASS II DEVICES.

Class II medical electrical equipment have a ‘double insulation’, avoiding any risk of persons touching

conductive part. In group 0 and group 1 locations, these devices do not need to be connected to equipotential

bonding and to the earth. In group 2 locations, however, class II medical devices must be connected to the local

equipotential bus bar.

d) PROTECTION THROUGH SYSTEMS WITH VERY LOW SAFETY VOLTAGE (SELV AND PELV).

Protection against both direct and indirect contact can also be acquired by reducing the voltage of the circuit to

maximum 25 V (alternating current) or 60 V (non-inverted direct current). This concept is called Safety Extra

Low Voltage (SELV) or Protection Extra Low Voltage (PELV). The power is then supplied through a safety

transformer or a battery. The circuits must be installed according to the standard IEC 60364-4 (clause 411.1).

The active parts must be insulated with a protection level IP XXD for horizontal surfaces within reach, and with

a level IP XXB for all other active parts.

In group 2 locations, the safety transformer must be powered by the insulation transformer of the medical IT

system. Moreover, all devices must be connected to the local equipotential bus bar.

SELV and PELV systems are rarely used, except for particular equipment such as scialytic devices and infusion

pumps.

e) SUPPLEMENTARY EQUIPOTENTIAL BONDING.

Applicable for all group 1 and group 2 locations.

‘Equipotential bonding’ is the connection of all conductive parts of the electrical system and conductive parts

extraneous to the electrical system with each other, and subsequently connecting this ‘bonding network’ to the

earthing network. Extraneous conductive parts include for instance metal pipes, metal windows, and iron

components of reinforced concrete. Equipotential bonding avoids that two metal parts could hold a different

electrical potential, entailing the risk on electrocution if they were to be touched simultaneously.

The general standard on electrical safety in buildings prescribes equipotential bonding for all rooms with a bath

or shower.

Standard IEC 60364-7-710 on medical locations obliges the equipotential bonding of all conductive parts

extraneous to the electrical system that are entering the same building.

Moreover, standard IEC 60364-7-710 requires supplementary equipotential bonding for all locations of group 1

and group 2. These rooms must be equipped with their own equipotential bonding bus bar to which all

electrical devices and all extraneous conductive parts are connected.

For group 2 locations, the electrical resistance between the (extraneous) conductive part and the bus bar shall

not exceed 0.2 Ω. Every conductive part should be connected separately to this bus bar without any additional

‘sub-node’, with the only exception of metal pipes and nearby sockets. The local bus bar can be placed on a

wall inside the location or immediately outside the room. If the group 1 or 2 locations should contain a bath or

shower, the metal parts of these installations must be connected to the bus bar as well. The cables used for the

equipotential bonding network must have minimum cross sections as prescribed by the standard. The bus bar

must be easy to access for inspection. It must be possible to disconnect each of the conductors from the bus

bar, and all cables of the equipotential bonding network must be clearly identifiable.



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2. ENSURING RELIABILITY

A first category of measures to provide a high reliability of power supply are those ensuring the selectivity of

the electrical protections. A protection has a high selectivity if it only disconnects these circuits where the

safety problem occurs, leaving the power supply to the other circuits intact. Horizontal selectivity is achieved by

subdividing the system into many different circuits with each a separate protection. For group 2 rooms and

Medical IT systems, IEC 60364-7-710 prescribes a separate protection for each group of plugs. Vertical

selectivity is achieved by ensuring that downstream protections trip before the upstream protections. For

example, downstream automatic circuit breakers should have a lower trip current than the upstream

automatic circuit breakers. In case of RCD’s or circuit breakers, the upstream protection should trip with a time

delay compared to the downstream protections.

A second category of reliability measures are those ensuring the availability of power supply in case of black-

outs or power interruptions. Although mainly a safety standard, IEC 60364-7-710 also prescribes certain rules

on this.

Those rules define, for certain category of devices:

In which circumstances the emergency power supply should connect

The maximum time delay in which the emergency power supply should connect (e.g. after maximum

0.5 s)

The minimum time duration the emergency power supply should be able to serve all vital appliances

(e.g. minimum 24 h)

A first category concerns all group 2 locations and group 1 appliances considered medically critical, for which

the most stringent rules should be applied. For example, the reaction time of emergency lighting above a

surgery table should be ≤ 0.5 s.

A second category includes all other electro-medical devices.

A third category includes all other equipment that is necessary for maintaining hospital services.

The IEC 60364-7-710 standard also includes rules on safety lighting. Safety lighting is obliged on the following

locations:

Group 1 and group 2 medical locations

Exit routes and safety exits, including the associated safety signs

Rooms containing cabinets, electrical switchboards, or generation sets

Rooms providing essential services, such as elevator motors, kitchens, air conditioning stations, data

processing centres etcetera

In case of a power interruption, safety lighting must be switched to an emergency power supply in ≤0.5 s for

lighting devices with a life support function and in ≤15 s for all other safety lighting devices. Emergency power

can be supplied in the same way as for the other safety devices (see further), or by individual batteries for each

device with an autonomy of at least 2 hours.

These IEC standards are complemented by the general European standard EN 8-38 on emergency lighting in

public buildings.



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The emergency power can be provided in different ways. For low power (typically under 400 kVA), a static

Uninterruptable Power Supply (UPS) will be used. This is a device that can provide near-instantaneous power

by means of batteries and associated electronic circuitry. However, it has a limited autonomy (10 to 30 min)

and must therefore be combined with a generator set (GenSet) for acquiring the required levels of autonomy.

For higher power rates (typically ≥ 400 kVA), a dynamic UPS can be used. This is a device that integrates the

UPS function with a diesel generator of flywheel for longer autonomy.

In each case, emergency power should be provided by at least two UPS devices supplying 50% or less of their

maximum power. In this way, overload problems are avoided and one UPS can stand in if the other one would

malfunction or drop out.

The type and size of the emergency power systems must be chosen with accuracy and according to case

specific criteria. Moreover, buying the right device alone does not suffice, you have to ensure it will always

operate as expected. It is therefore essential that the emergency power supply is installed by qualified

experts and that its performance is tested on a regular base. As testing procedures are not included in the IEC

standard, it is recommended to follow the prescriptions from manufacturers. Some EU countries hold a

national law on mandatory periodic testing of emergency power supply systems (e.g. Italy).

3. FUNCTIONAL EARTHING

The earthing of electrical devices and conductive parts is not only necessary for safety reasons, but also to

ensure the well-functioning of the equipment. All electric and electronic devices send out electro-magnetic

signals, which may disturb other devices. Preventing such disturbances is called functional earthing or ensuring

Electro-Magnetical Compatibility (EMC). Functional earthing is not included in the hospitals’ standard IEC

60364-7-710, but in another section of the same general standard (i.e. IEC 60364-7-707). To ensure EMC, a

classical connection to the earth is not sufficient. Designing an earthing network that filters out all mutual

disturbances is a complex task, to be executed by a specialized engineer.

4. EQUIPMENT SPECIFICATIONS

Standard IEC 60364-7-710 contains some limited prescriptions on the electrical safety of medical devices. More

extensive prescriptions for medical electrical equipment are listed in a series of standards with number IEC

60601-xx.

On top of these, the technical specifications of equipment manufacturers sometimes mention EMC guidelines

for their devices. Useful as that may be, an earthing network should always be design ed from a system’s

perspective, and not from the perspective of one device. Moreover, equipment specifications tend to focus on

functional earthing alone, without taking electrical safety into account. In some cases, functional earthing and

earthing for safety reasons can come in conflict with each other. It is therefore important to leave the design of the earthing network to a specialized engineer who can guarantee both EMC and electrical safety.

5. PROTECTION AGAINST LIGHTNING

Protection against lightning strikes is included in the general safety standard IEC 62-305. Two different risks

have to be evaluated: the risk of losing a human life, and the risk of material damage and its corresponding

financial losses.

According to the IEC standard, the former risk should be no higher than 1 loss of life out of 100.000 direct

lightning strikes on the building. The standard proposes clear protection measures to reduce this risk.



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Concerning the latter, the IEC standard only provides an assessment method for evaluating the financial risk.

Having this assessment at hand, it is up to the users to decide how much they want to invest in additional

protective measures.

B. ENERGY EFFICIENCY Once the safety and reliability of the electrical system are guaranteed, attention can go to energy efficiency. A

reduced energy consumption can be a crucial element in mitigating the continuous rise of hospitalization costs.

Most energy efficiency gains in electrical installations are based on one physical principle: the energy losses in a

conductor are inversely proportional to its cross section. This rule counts for cables as well as for the windings

of electric motors and transformers.

The minimum cross-sections of electricity cables is prescribed by the international safety standard IEC 60364.

However, those standards only take safety aspects into account and not the energy efficiency. Over-sizing the

cross-section compared to this standard is in most cases worthwhile the investment. The cross-section with the

lowest Total Cost of Ownership (TCO) can be calculated out of the load pattern, future electricity prices, and adiscount rate. The resulting energy savings will also positively influence the ecological footprint of the

installation.

Transformers are another part of the electrical system where significant savings can be achieved. Transformers

may seem to have a relatively high energy efficiency compared to other electrical equipment (typically 98% to

more than 99%), but they work in continuous operation and have a long life span (typically 20 to 30 years). As a

result, a small efficiency increase can add up to significant savings over the lifetime of a transformer. In the

large majority of cases, high efficient transformers have an attractive life cycle cost. Pay-back periods are often

less than two years. In addition to the financial premiums, the energy savings also entail significant

environmental benefits.

C. OTHER IMPORTANT ISSUES CONCERNING THE ELECTRICAL SYSTEM

Some other important issues concerning the well-functioning of the electricity system are not included in the

IEC standards:

Mutual influences between devices affecting availability. Several medical devices (X-ray machines,

MRIs, nuclear medical devices) are particularly sensitive to the quality of the electrical power supply.

This quality is not only put at risk by power dips or interruptions on the public grid, it can also be

affected by the very medical equipment itself. Devices involving a dynamic load (e.g. X-ray machines)

can even cause power quality problems for the entire hospital facility. A proper design of the electrical

system can avoid such problematic mutual influences.

The patient’s quality of life. The IEC standard is adequate for ensuring electrical safety and the

reliability of life-support functions. But patients want more than just that. The quality of life of

patients inside the hospital can be enhanced by, among other things:

o Minimising the unnecessary repetition of exams. This requires power availability rules which

are much more stringent than those of the IEC standard.

o Providing clear information, and instructions on what to do, in case of a power interruption



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Proper training of nurses and doctors. A lack of the personnel’s knowledge on electricity might lead to

improper use of electro-surgery equipment, affecting electrical safety and availability. An adequate

and regular training programme on this topic could prevent such problems.

II. HVACDespite being a thermodynamic system, the Heating, Ventilation and Air Conditioning (HVAC) of a hospital has

a strong interaction with the electrical system.

A. INDOOR AIR Q UALITY (IAQ)

The HVAC system for a hospital has to fulfil all classical comfort needs of a public building, but it also has

requirements that go beyond just that. As patient’s stay in their room 24 hours a day, maintaining the right

temperature, humidity and ventilation level is essential for supporting their recovery. Another crucial task is to

maintain the Indoor Air Quality (IAQ) in all patient’s environments in order to limit the bacterial concentration

and to avoid any cross-contamination between the patients. More particular for operating rooms, the IAQ is

submitted to stringent requirements. To maintain the right IAQ, not only temperature, humidity and ventilation

of the each room are regulated, but also the pressure level relative to the surrounding spaces. All these

requirements result in a complex HVAC system that will at least use 50% of all energy consumption of the

hospital.

B. RELIABILITY VERSUS ENERGY EFFICIENCY?

As HVAC is not only crucial for the patients’ comfort, but also for their health, the reliability of the system is of

utmost importance. This means that sufficient redundancy has to be built into the system. Standby equipment

has to be installed to take over in case the first line equipment is out of service. As a result of this redundancy,the capital investment cost of a hospital’s HVAC system can mount high. This makes it hard to invest even more

in the equipment in order to improve its energy efficiency. Nonetheless, such an investment can significantly

reduce the Total Cost of Ownership of the installation.

The following are three basic concepts to reduce energy consumption of the HVAC system:

1. MOTOR SYSTEM EFFICIENCY

HVAC systems include many electrical motors, mainly pump and fan motors. Important efficiency gains in those

motor systems can he achieved.

A first step is the proper sizing of the motor, as the energy efficiency of motors drops significantly when

operating above or under their nominal load. This means that the HVAC system should be designed as efficient

as possible in order to minimize the required motor power. Later efficiency gains at the mechanical side will

have a reduced impact if they result in a motor operating under its rated power.

For systems requiring a variable output, the type of motor control that is used if crucial for its efficiency. Best

practice is to avoid mechanical control systems (throttles, gearboxes...) and change the output by means of a

variable speed drive (VSD) connected to the motor. A throttle has a typical efficiency of 66%, while the

efficiency of a VSD can easily mount up to 96%.

A large difference in energy efficiency can also be made in the electrical motor itself. While a standard

induction motor has an efficiency of typically 90%, a High Efficient Motor (HEM) can have an efficiency of 95%

and more. In the EU, the efficiency of induction motors is labelled Eff 3, Eff 2 and Eff 1, the latter being the



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highest efficiency category. With the exception of motors with a very low intensity of use, Eff 1 motors will

always have the lowest Total Cost of Ownership. In 2008 a new international standard for the efficiency of

electric motors was introduced (IEC 60034 – 30). On the contrary to the EU label, the numbers corresponding

with this new standard go up with increasing efficiency (IE 1, IE 2, IE 3, IE 4). The lowest efficiency category of

this new international label (IE 1) corresponds approximately with the middle category of the EU labels (Eff 2).

The following example shows how the efficiency of a pump system can be increased from 31% to 72% by

selecting the right equipment:

Conventional pumping system High efficienct pumping system

Device Efficiency Device Efficiency

Standard Induction Motor 90% High efficient induction motor 96%

- Variable speed drive (VSD) 95%

Coupling 98% Efficient coupling 99%

Pump 77% Efficient pump 88%

Throttle 66% -Pipe 69% Energy efficient pipe 90%

Total pumping system 31% Total pumping system 72%

(Source: ‘Efficiency in Motor Driven Systems’, Ronnie Belmans, Wim Deprez, KULeuven)

Motors are often integrated into bigger entities purchased entirely from an OEM. This barrier can be countered

by writing the use of Eff 1 (IE 3 or IE 4) motors and VSDs into the general equipment specifications of the

hospital.

Note that also operation and maintenance conditions can affect the efficiency of a motor system. An important

factor to verify is the quality of the power supply. Voltage unbalance and harmonics are just two examples of

power quality issues that can seriously deteriorate motor efficiency.

2. HEAT RECUPERATION

Heat (or cooling) recuperation can be realized by integrating heat exchangers in the ventilation system,

transferring heat from the outgoing air to the incoming air or vice versa.

In case the hospital has a large cooling need (situated in a hot climate), a heat pump can be connected to the

chiller plant of the air conditioning system. In this way, the heat can be recuperated for producing hot water.

3. CO-GENERATION

Since a hospital has a large and relatively constant need for heating/cooling and hot water, it might be

advantageous to install a co-generation system on site.

The basic principle of co-generation is to simultaneously produce electricity and heat. The overall efficiency of

such a system is higher than if electricity and heat are to be produced separately.

Various types of co-generation technologies exist. In case of a hospital, co-generation with a gas motor is the

most obvious choice. Such a motor is fuelled by natural gas and drives an electricity generator. Depending on

the needs, heat can be recuperated in the intercooler (30 – 80°C), the lubrication oil (75-95°C), the cooling

water (75 - 120°C) and the exhaust gasses (400 – 550°C) of the motor.

A co-generation system should be dimensioned according to the heat requirements of the premise. As the

system will be coupled to the electricity grid, any surplus in electricity can be supplied to the grid, and any

shortage can be taken from the grid. But any heat surplus will inevitable be lost. Such heat losses seriously



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compromise the efficiency of the system. To avoid this, the co-generation system is best conceived as an

installation for heat production, while electricity is seen as a bonus that helps to pay-off the investment.

That said, the electricity from the co-generation unit that is consumed locally will be less expensive than grid

electricity, as it avoids transmission and distribution charges. In many countries, the electricity and heat

produced through co-generation is rewarded with certificates, recompensing for the carbon emission

reductions.

In some cases, the co-generation unit can be used as an emergency generator. This should not prevent the co-

generation unit to be dimensioned based on heat demand. Designed in this way, the unit can only be used as

an emergency generator if its electrical output at least equals the required emergency power.

III. COMPRESSED AIR

1. MEDICAL AND TECHNICAL COMPRESSED AIR

The international standards on compressed air in hospitals distinguishes between medical and technical

compressed air.

Compressed air that drives surgical tools is considered ‘medical compressed air’ and has to follow the

standards of ‘medical gasses’. More specifically, standard ISO 7396-1:2007 specifies requirements for design,

installation, function, performance, documentation, testing and commissioning of the distribution systems of

medical gasses.

Central medical gas systems are class IIb medicinal products. This means equipment manufacturing for those

systems should comply with ISO EN 7396 – 1.

Both medical and technical compressed air have to comply with ISO 8573-1:2010, which specifies the purity

classes of compressed air with respect to particles, water, and oil. ISO 8573-1:2010 also specifies gaseous andmicrobiological contaminants.

2. ENERGY EFFICIENCY OF COMPRESSED AIR

Compressors – no matter whether they supply a medical or a technical compressed air system - are driven by

an electric motor. Consequently, what counts for fans and pumps, also goes for compressors: by opting for high

efficient motors (HEMs) and variable speed drives (VSDs), important energy efficiency gains can be achieved

that significantly reduce the Total Cost of Ownership of the installation (see also: HVAC, motor system

efficiency)

Other important energy savings in compressed air systems can be made by:

Limiting demand: avoiding inappropriate use of compressed air, and limiting pressure drops to real

needs

Reducing distribution losses through a good design of the piping network, regular maintenance, and

the repairing of leaks.

Reducing the air inlet temperature: approximately 0.3% of the energy is saved with each degree. By

placing the inlet outside, at the north end of the building, and far away from heat sources,

temperature can often be reduced by 10°C, resulting in energy savings of 3.5%.

Heat recovery: installing a heat recovery system can have pay-back periods of less than two years



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Central control: in larger, more complex compressed air systems, a centralized control system will

ensure energy efficient responses

IV. BUILDING AUTOMATION AND AUXILIARY SYSTEMS

1. AUXILIARY SYSTEMS

Many auxiliary systems in hospital buildings are driven by electric motors. Examples include elevators,

automatic sliding doors and automatic sun blinds. For those motors, just like for the ones in HVAC and

compressed air systems, opting for a High Efficient Motor (HEM) controlled through a Variable Speed Drive

(VSD) can significantly reduce their energy consumption and the Total Cost of Ownership of the system.

2. CONVENTIONAL BUILDING AUTOMATION SYSTEMS

In many buildings of the tertiary sector, building automation systems are used to improve control of lighting

and HVAC systems and limit their energy consumption. Those systems can, among other things, switch off the

lights when enough natural light is entering the room, switch off the air-conditioning when windows are

opened, set the heating at lower during night-time, automatically control sun blinds, etcetera. In buildings thatoperates 24 hours a day, 7 days a week, like a hospital, the efficiency gain achieved by those systems is limited

– although it is sill worthwhile investigating their potential benefit. Moreover, hospitals also include rooms that

are only operational during working hours – think of offices for instance. And in many cases, building

automation systems can increase the feeling of comfort of patients and personnel.

According to the European standard EN 15232, buildings with a class A building automation system achieve

significant energy savings compared to buildings with no building automation system at all. The savings in

electrical energy are estimated to be 9%, the savings in thermal energy are estimated to be 34%.

3. PATIENT ASSISTANCE AND TELE-MEDICINE

Assistance to patients is preferable automated as much as possible. Patients will feel more self-supporting andless embarrassed if they are assisted by an electrically driven system than if they have to call on the personnel

for all help. In this way, the contact with the personnel will be more dedicated to what automates cannot

provide: human conversation.

Automated diagnoses and check-ups can increase the patient’s feeling of control. This increased involvement

will often boost the patient’s esprit de corps and in this way speed up recovery.

Some of those systems can also be used outside the hospital. By returning home faster, the patient’s quality of

life will improve while treatment costs are reduced by saving on manpower. A positive example of this concept

is the Carme project in Catalunya, Spain, providing tele-medecine for cardiac patients. Thanks to this project,

the perception of the patient’s quality of life increased with 72%, while the days in hospital of cardiac patientsdecreased with an impressive 73%.

To fully harvest the advantages of tele-medecine, three important aspects require attention. First of all, the

hospitals ICT system should be well-adjusted for integrating the tele-medecine system and for reliably

processing all signals. Second, doctors and patients should have full confidence in the system, otherwise it will

only function as an addition on top of to the current techniques and costs will rise instead of going down. This

confidence can only be expected when choosing mature systems with proven performance, and when

appropriate training for doctors and all personnel involved is provided.



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4. HOSPITAL COMMUNICATION SYSTEMS

Concerning the communication systems in hospitals, reliability is the main point of attention. Achieving a high

reliability for communications systems is only possible when the power supply to those systems is equally

reliable. For the reliability of the power system, see chapter I.1.2 Ensuring reliability.

V. ROUND UP

A hospital’s first concern regarding the electrical installation is to ensure safety and the reliability of life -

supporting equipment.

The international standard IEC 60364-7-710 on medical locations in buildings is very comprehensive regarding

electrical safety. It classifies medical rooms into three groups and prescribes regulations for each of these

groups.

The same standard also includes some essential rules for ensuring a reliable power supply to vital equipment

and emergency lighting. However, several additional elements regarding reliability have to be considered. To

avoid that electr(on)ic devices disturb each other with electro-magnetic signals, a proper functional earthing is

required. This is regulated by the standard IEC 60364-7-707. It requires, however, a specialized engineer to

implement it.

A specialized engineer is also required for ensuring a proper power quality in the hos pital’s electric network.

This does not only depend on the reliability of the public grid; often it are the medical devices itself that inject

‘electric pollution’ into the local network. Ensuring power quality at the point of connection with the grid alone

is consequently not sufficient.

The ambition of a hospital concerning the reliability of power supply should also go beyond the supply of life-

supporting equipment. The patient’s quality of life can be improved significantly by minimizing the downtime

of any type of electrical device.

Energy efficiency is often treated stepmotherly in hospitals, as it less vital than safety and reliability. This is a

pity, because energy efficiency improvements can result in significant reductions of the total cost of ownership

of the installations. Those cost reductions can be of benefit for the hospital, the patients, and public

healthcare. One way to minimize energy losses, is to choose a larger cross-section for electric conductors than

is required by safety prescriptions. High efficiency transformers can also make a significant difference. Perhaps

the biggest efficiency gain that can be made is by adopting High Efficient Motor systems. Electric motors are

integrated at various places in hospitals: in the fans and pumps of the HVAC system, in the compressors for

medical and technical compressed air, and in auxiliary systems like elevators and sliding doors. As those

systems are in general purchased through OEM’s, energy efficiency should be tackled in the general

prescriptions to the OEM.

For answering the hospital’s heating and hot water needs, a co -generation system with natural gas motor will

in many cases be advantageous. Such a system simultaneously generates heat and electricity, with a higher

efficiency than in case of separate generation.

Another potential measure for reducing the hospital’s energy consumption is the implementation of building

automation systems. When adopted properly, those systems can reduce the thermal energy need with up to

34%.



14

A. REFERENCES

IEC 60364-7-710 Electrical installations of buildings - Part 7-710: Requirements for special installations or

locations - Medical locations

IEC 60364-7-707 Electrical installations of buildings. Part 7: Requirements for special installations or locations.

Section 707: Earthing requirements for the installation of data processing equipment

IEC 61557-8 Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment

for testing, measuring or monitoring of protective measures - Part 8: Insulation monitoring devices for IT

systems

IEC 62-305 Protection against lightning

IEC 60034 – 30 Rotating electrical machines – Efficiency classes of single-speed, three phase, cage-induction

motors

ISO EN 7396 – 1 Medical gas pipeline systems -- Part 1: Pipelines for compressed medical gases and vacuum

ISO 8573-1 Compressed air -- Part 1: Contaminants and purity classes

electricity system for hospitals

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