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THE IMPLEMENTATION A D EFFECTIVENESS O A I R INFILTRATION
STANDARDS IN BUILDINGS
5th A I C Conference, October 1-4 1984, Reno, Nevada, USA
PAPER 6
ENERGY PERFORMANCE STANDARDS REGARDING A I R INFILTRATION OF
BUILDINGS IN SWITZERLAND
CONRAD U. BRUNNER
A r c h i t e c t and Energy Consultant
L i ndenhofstrasse 15
CH - 8001 Zurich
S w i t z e r l and
SYNOPSIS
The Swiss performance standard f o r energy conservation in buildings
SIA* 380/1 i s explained. This standard leaves a i r i n f i l t r a t i o n and
other d e t a i l decisions t o planners i f minimum performance levels
are met. Calculation procedures f o r heat balances based on a
standard-occupancy are described. Tools to achieve optimum space
heating and ventilation rates are explained. Instrumentation for
checking the thermal performance of the house in operation i s
defined.
*SIA: Swiss Society of Engineers and Architects
1. TNAD
PERFORMANCE STANDARDS V COMPONENT S A D R S
S
Different countries have chosen different ways so f a r t o limit
building energy consumption. Most countries have started w i t h
component standards, established as a means t o protect the consumer
against deficient products. The large number of DIN-Standards in
Germany [ref. I ] and the Californian Energy Conservation Standards
[ref. 21 are typical examples f o r s e t s of building component
s
standards. A f o r quality standards in complex systems as cars,
bui 1dings or some industrial products (tv-sets e t c . ) another method
i s equally established: the performance standard of an e n t i r e
system which i s treated as a black box. Standards f o r the fuel
consumption of cars are a good example of t h i s method where c l e a r
testing situations have been established. The advantage of t h i s
l a t t e r approach i s a larger freedom f o r designers and producers t o
come up with solutions they find best under given economical and
technical conditions. The standard serves only as a precisely
stated goal, where the solution can be freely chosen among a
multitude of always changing paths. Switzerland has chosen with
SIA 380/1 [ref. 31 t h i s l a t t e r method t o limit energy consumption
of buildings a f t e r a period of increasing numbers of component
standards and responding t o a growing concern of the professional
community not t o be completly regulated by detailed s t a t e legisla-
tion. Heating i n the system "HOUSE" i s devided into two subsystems:
- net heat consumption
- annual coefficient of performance
Both have to comply w i t h the respective s e t s of standards. Electric
consumption, the use of ventilation, a i r conditioning and cooling
equipment are defined separately.
The SIA standard 38011 (1984) gives a calculation procedure to
compute the two s e t s of standards and also allows the use of an
easier method f o r small buildings below 500 m gross f l o o r area
2
which i s based on the older component standards w i t h more stringent
val ues.
Air i n f i l t r a t i o n i s therefore not treated in detail in t h i s
standard. B u t i t i s included in the calculation procedures f o r
heat l o s s , i t i s specified in the standard-occupancy and i t i s
also treated in the component standards f o r small buildings
(window joints etc. ). According t o a s e t of recent simulations on
t e s t houses the a i r i n f i l t r a t i o n share amounts to some 20 - 40 %
of the net heat loss [ref. 41, with well insulated houses tending
to the upper value.
2. OL
T O S TO ACHIEVE OPTIMAL ENERGY PERFORMANCE
I t i s obvious t h a t an optimisation of the heat balance of a building
including losses and gains places great concern on the "optimum"
ventilation. This means t h a t i n order t o comply with a legal
standard you may not design a i r t i g h t buildings and prevent people
from getting a sufficient amount of fresh a i r . Therefore, the
standard i s divided into three information sets:
- construction d e t a i l s t o improve airtightness, avoid unnecessary
hvac equipment, orland t o u t i l i z e heat recuperation ( t a b l e 1 )
- standard-occupancy defined a s a s e t of a i r change rates depend-
ing on use; these values have t o be applied i n the calculation
procedures (tab1e 2)
- user related a i r i n f i l t r a t i o n of a well designed house should not
be t o t a l l y dependent on everyday compliance of a l l occupants.
Advice and training has to be given t o the normal user because
most s t i l l open windows in wintertime t o "moistenn the dry room
air!
A f o r meeting the performance standard of a project i n t h e design
s
stage only t h i s standard-occupancy i s relevant; construction d e t a i l s
can be freely chosen according t o local practice*.
Table 1: Criteria f o r use of mechanical ventilation and a i r
conditioning
b
- External influences . noise
. a i r pollution
. safety
. extreme alpine conditions
- Building parameters . offices with deep spaces (< 6 m2)
. offices with large spaces ( > 200 m 2 )
internally located and underground areas
. high r i s e ( > 12 s t o r i e s )
- Use conditions . high occupant concentration (< 3 m2/per-
. toxic fumes and smells (smoking) son)
*
. high internal heat production (>45 W/m2)
Note: the Swiss climate i s relatively moderate with an average out-
door temperature in Zurich in January of -1°C and in July of +18OC;
of course there a r e southern zones with some 3 K higher average
temperatures and extreme temperatures in the mean summer day of 33°C.
* Many of the d e t a i l s in the AIC-handbook of 1983 will probably be
rejected by the average Swiss craftsmen because the d e t a i l s
involve elaborate f i t t i n g , which a r e infeasible as on-site work.
Air change r a t e s i n t a b l e 2 i n t h e standard-occupancy a r e defined
a s minimum - maximum values. T h i s means t h a t without s p e c i f i c
and
technical i n s t a l l a t i o n s they cannot be reduced and they should not
be increased. Of course t h e a i r change r a t e s can be reduced during
non-occupied times ( n i g h t s , weekends, hol idays) t o a minimum of
some 0.2 h'l according t o necessary humidity l e v e l s ( f i g u r e 1 ) .
With t h e introduction of heat-recuperators and controlled venti-
l a t i o n t h e net a i r change r a t e can be reduced. Due t o the minimum
a i r flow and additional r e s i s t a n c e of f i l t e r s i n used conditions,
the a i r change r a t e s cannot be very f a r below t h e r a t e s s t i p u l a t e d
in the standard-occupancy.
Table 2: Standard-occupancy: a i r change r a t e s (annual mean
values)
#.
One family housing 0.4 h-1
u
M 1 t i family housing 0.6
Offices , commerci a1 0.8
Air t i g h t n e s s of e n t i r e building* 0.2
t
* With a l l doors, windows and o t h e r openings closed.
Figure 1 : Air change r a t e (one day cycle)
(Example f o r mu1 t y family housing)
A i r Change Rate
The main issue i s t o achieve superior indoor temperature control
in order t o use the available f r e e heat from solar and indoor
sources t o the maximum. This will prevent ill-advised users from
opening windows excessively t o control overheating (figure 2 ) .
Therefore, i t i s not only a question of educating users, but of
giving them the proper tools t o get the amount of heat they really
want [ref. 51. An additional feedback to users i s cost-sharing
according t o the amount of heat consumed. This will of course
dramatize t h i s e f f e c t in a positive way.
Figure 2: Room temperature (one day cycle) [ref. 61
(Example f o r one family housing)
Room Air Temperature
25O
12 1 8 hours 24
On the other hand i t should be emphasized, that any quick change
during the day in the desired room a i r temperature will n o t bring
large heat savings due t o the i n e r t i a involved in well insulated
and t i g h t l y f i t t e d houses (figure 3 ) . This i s especially true in
the relatively heavy structures (over 600 kilograms per square
meter) common in Switzerland and Central Europe. Such houses have
a time constant of 150 t o 250 hours, which leads to a temperature
reduction due to night setback in normal winter conditions of only
1 K during night hours.
Figure 3: Night setback: cooling effect of a i r temperature
[ref. 61
Room Air Temperature
00 start 06 1 2 hours 18 cooling time 24
Any heating system depending solely on north oriented external
temperature sensors and a fixed linear relationsship with heating
system-temperatures cannot satisfy the stated objective of superior
i nternal temperature control s.
The other central issue i s to minimize heat loss due t o infiltra-
tion which i s generally not synonimous to minimal a i r change rates.
Good room temperature controls of the heating system invite users
naturally t o a energy conscious behavior. The "synergetic link"
[ref. 51 increases the effect of energy savings: good insulation
and tight joints plus indoor sensitive room a i r temperature controls
and
improves comfort conditions for the user - reduces energy consump-
tion a t the same time.
E S RN O S M TO
M A U I G ENERGY C N U P I N
I n order t o assess the process of designing, building and occupy-
ing an energy efficient building the ultimate performance check
i s only possible with measuring techniques. Therefore, a minimum
set of measuring instruments i s defined for a heating system
(table 3 ) . With these instruments every owner or control 1 ing board
can check, after a starting period of 2 years, the actual energy
consumption and compare i t to the design values according t o the
following formula:
N
Eh = - (MJ/mZSa)
h
eta
: annual specific end-heat use (MJ/mZSa)
Eh
computed annual specific net heating demand (MJ/mZ.a)
Nh:
eta: mean annual COP (-)
Table 3: Measuring instruments
I
'
- Counter of operation hours
- Start impulse counter
- Fuel consumption measurement ( o i l , gas, electricity etc. )
- Thermometer for temperatures of the exhaust stack
- Meter for domestic h o t water
There i s a tendency t o include all these instruments in a package
in the standard heating p l a n t and t o install performance meters
t h a t show an annual mean COP on a LCD.
f
O course there will be a large band of deviations between calcu-
lated and measured values that can be divided into the following
four categories:
- design changes (macro of detail) after the energy calculations
have been made
- bad in situ details due t o bad s i t e supervision
- unnormal cl imate conditions (severe winter etc. )
- unnormal user behaviour (higher temperatures or ventilation
rates etc.)
Initial drying-out and wood-shrinking periods have to be monitored
and can generally be excluded from an analysis after the f i r s t two
years of normal operation. First year of operation problems with
regulation and optimisation efforts have t o be taken into account,
also. The band of deviation t h a t generally i s accepted with
standard climate data a r e deviations of -10 % t o +20 % of the
annual energy consumption. Larger deviations have to be investi-
gated and causes identified.
For t h i s procedure i t i s necessary t o s t i p u l a t e the duty of house
owners t o keep energy consumption records and t o o f f e r them f o r
public checks annually. For larger buildings monthly records a r e
recommended. For the safe hand1 ing of possibly pol 1uting fuel s
t h i s r u l e has long been established in Switzerland. The data of
gas, e l e c t r i c i t y and d i s t r i c t heat consumption on the other hand
are readily stored in s u f f i c i e n t l y accessible data bases.
Such a measuring procedure i s the new and final check of the build-
ing qua1 i t y t h a t should be included in every builder's contract.
4. POLITICAL AND ADMINISTRATIVE IMPLICATIONS
The administrative boards can control one s e t of standards t h a t
characterize the e n t i r e energy system o r can go back and t r y t o
check a l l the detail components t h a t have been regulated so f a r .
A c e r t a i n resistance to change from component t o performance
standard e x i s t s also in Switzerland, even i f the new system seems
easier t o handle and less time consuming with limited manpower.
Due t o intervention of the local s t a t e s the formal legal introduc-
tion of SIA 380/1 will be granted only a f t e r an i n i t i a l t e s t i n g
period of some 2 years wherein a1 1 pub1 i c buildings will have to
comply a1 ready with the new standard.
The Swiss building stock has tended towards more e f f i c i e n t energy
use since 1975 as can be shown in figure 4. This i n i t i a l success
will continue in the future w i t h the introduction of SIA 380/1.
Figure 4: Specific heat consumption in housing [ref. 7 , 8)
Relative Frequency
Number of Cases R L
1 I
1 I
40%
new one-
30%
one-family houses
after retrofit
20%
10%
0
0 200 400 600 800 1000 1200 1400 1600 1800
specific annual energy consumption for space heating E h [MJ/mZ.al
C N WE GMNS
A K O LD E E T
I wish t o thank the SIA, the Swiss Department of Energy BEW and
the Swiss National Energy Research Fund NEFF f o r supporting t h i s
y
work and a l s o m collaborator mainly Miklos Kiss and the chairman
of the SIA 380/1 Committee Kurt Meier f o r t h e i r valuable contri-
butions.
REFERENCES
[I] I
German I n s t i t u t e f o r Normalisation: DN Catalogue,
Berl in 1980
[2] California Energy Commission: Regulations establishing energy
conservation standards, 1978
[3] Swiss Society f o r Engineers and Architects (SIA): Energy in
buildings, Recommendation SIA 380/1, Zurich 1984
( f i n a l d r a f t version)
[4] Brunner C.U., Kiss M. e t a l : Energy Consumption, simulation
on t e s t houses, Zurich 1982 (unpubl ished)
[5] Brunner C.U.: Potential and l i m i t s of energy savings in the
Swiss building stock, 4th AIC Conference, Elm Switzerland
1983
[6] Swiss Department of the Interior: Energy savings in new
buildings, Bern 1981
[7] Brunner C.U., Muller E.A.: Strategies f o r energy conservation:
Development of specific heat consumption in the building stock,
in SI+A Nr. 30, Zurich 1983
[8] Brunner C.U., Muller E.A.: Changes in the structure of energy
consumption in buildings [SVEG], Zurich 1984 ( d r a f t ,
unpublished)
