AU601795B2 - Roof space ventilation system - Google Patents

Description

I

L

l l.i-Y-I~I__L_1_I-_Lli- i 1 79 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE

SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Class In Application Number: Lodged: Form t. Class It Complete Specification-Lodged: Accepted: Published: Priority Related Art: This documqnt contains the amendments made under Section 49 and is correct for printing.

Name of Applicant: Address of Applicant: TO BE COMPLETED BY APPLICANT W H-I-NKING--NGASP-VENTI-LATIEN- SYSTEMS-PT-Y-.-LTB pooo-DM lcT\ Tc 0 Pq-%A. L-Ta.

337 Whitehorse Road, Balwyn, Victoria, 3103 1'' Actual Inventor: Address for Service: SANDERCOCK, SMITH BEADLE 207 Riversdale Road, Box 410) Hawthorn, Victoria, 3122 Complete Specification for the invention entitled: ROOF SPACE VENTILATION SYSTEM The following statement is a full description of this invention, including the best method of performing it known: to me:j 2 This invention relates to a ventilation system.

More particularly, the invention relates to a ventilation system suitable for ventilating a roof space, thereby helping to maintain a desirable temperature in a living space located beneath the roof space.

One of the most significant problems associated with dwellings in Australia, and in many other countries and geographical areas, is the necessity of achieving a living space temperature between 200 and 25 0 C at all times of the year.

0 It is common practice at present to compensate the fixed undesirable characteristics of insulation and humidity control by the utilization of refrigerated air conditioning, heat pumps, evaporative air conditioning and/or 15 increased air velocity systems, to reduce the excessive, undesirable heat in the living space during periods of hot weather, which occur most frequently and with greatest severity and duration in the summer, which in Australia occupies the months December to March.

In cooler months or periods it is accepted common practice to utilize room or central heating to increase the living space temperature into the aforementioned desirable, comfortable temperature range. Both the cooling and heating means currently utilized to achieve the necessary compensations are profoundly undesirable and are also excessively expensive and energy dependent for their operation in achieving their objectives.

Insulation material, which is dependent on exhaustable energy and fuel for its production, is commonly installed above the ceiling of a dwelling or other structure. Ceilings represent a large and thermally important area of buildings.

A tendency exists to instal insulating material having a greater thermal resistance in an effort to restrict the inflow of heat to the living space, which restriction achieves at the expense of greatly reduced dissipation of heat from the living space in the cool of the evening, as the temperature gradient is far less. This results in less thermal comfort in the living space, and if high temperatures occur the following day the living space will commence heating from the S 5 t C t 20 I" "1PU-UL-"*~lli~illlX-( I~IC-"4"C~" -3higher temperature at which it has been held by the insulation.

To correct this it is necessary to use a heat pump.

An object of this invention is to provide a ventilation system which will, by the use of passive means, help to provide greater comfort in the living space of a dwelling through the provision of a more constant desirable temperature in the living space.

The scope or spirit of the present invention is a ventilation system which by passive or natural means maintains the living space, which includes rooms of a structure, particularly homes, throughout the year within a more uniform and desirable temperature range. Incorporated within the scope and spirit of this invention is the generally accepted advantage of energy conservation generally, together with optimising the use of insulation material and savings in production resources. No electrical, fossil or other exhaustible or manufactured fuel need be used for the operation of the system.

Accordingly, the invention provides a passive roof space ventilation system for a building having eaves, including an air outlet adapted to vent relatively warm air located in said roof space from said roof space to the atmosphere, and an air inlet located in use at the eaves level of said building, through which air inlet relatively cool external air is adapted to flow to displace said relatively warm air vented by said air outlet, said air inlet including a duct defining an air passage, said duct having an air entry end and an air exit end, said air entry end being adapted to be located, in use, at said jbspe. 001/boundy 90 6 27 i l~ -4eaves level, said air exit end being adapted to be located, in use, at a higher level in said building than said air entry end and at a level such that it protrudes into said roof space and such that said relatively cool external air passing through said duct and exiting therefrom at said air exit end will pass across and above a substantially horizontal interface between said roof space and a living space of said building, said air outlet being located, in use, at a higher level in said roof space than said air inlet.

An embodiment of the invention, which may be preferred, will be described in detail hereinafter with reference to the accompanying drawings, in which:- Figure 1 is a partially cut-away perspective view of a ventilation system outlet; Figure 2 is a perspective view of fire damper assembly to be associated with the outlet of Figure 1; Figure 3 is a diagrammatic elevational cross-section through a dwelling roof space; Figure 4 is a perspective view from below of a ventilation system inlet; and Figure 5 is a diagrammatic side elevation of a fire-fuse.

Referring firstly to Figure 1, the outlet vent 10 includes a hood 12 which serves to keep both rain and increased air pressure from winds out of the tube 14, which is shown as a tubular member secured to the flat underside of hood 12 by spot welding, but this embodiment and the invention are not restricted to that joining method.

V The tube 14 has a screen portion 16 which extends around 20 t2 .t 5f jbspe.OO1/boundy 90 6 27 1%

I

3r i -4L1athe circumference thereof, which portion 16 allows air to pass therethrough, but prevents the passage of birds, animals such as mice and possums, leaves or the like. Flashing 18 is secured to the tube 14, for attachment of the ae cc jbspe.01/boundy 90 6 27 1 r -xx

I

outlet 10 to a roof or suitable surface. Additional flashing in the form of a strip 58, preferably formed from lead, allows a neat, close-fitting appearance to provide continuity with the roof surface. The lead allows the flashing to conform with any profile and the mass of the lead assists in holding down the vent 10 to the roof. The flashing 18 may have upturned edges 68. Other suitable materials may, of course, be used.

Within top portion 20 of tube 14 there may be disposed means 70 (Figures 2 and 5) to close tube 14 and thereby stop the flow of air therethrough. The means 70 will be described hereinafter.

Figure 3 shows the roof space 22 of a dwelling 40. At least one outlet 10 is fitted to the outside of the roof i± or walls enclosing the roof space 22 or upper area of the building or structure, the tube 14 allowing communication between the air around the dwelling 40, and the air in the roof space 22 between the roof 30 and the ceiling 32, the latter often being fitted with a form of insulating material 72.

Under the eaves 42 of the dwelling 40, there is located at least one inlet vent 34 (two of which are shown in Figure The vents 34 are not by necessity located under the eaves 42, but may be located elsewhere. A vent 34 is shown in detail in Figure 4. It consists of a base plate portion 46 with a grating or screen 36 to allow passage of air but to prevent the passage of birds, animals or the like. The vent 34 has an upstanding duct 38 extending from the Sboundary of the grating 36 up to a level which will permit 1 i ~rl~s 900103,!MWSPE.011,roof.spe,

T.

2- I

I~Y

the denser, cooler air drawn in through the vent to flow onto the upper or top surface of the ceiling 32 and/or the surface of ceiling insulation 72, as shown by the arrows in Figure 3. In this way the temperature gradient and consequential heat transfer through the ceiling 32 or ceiling insulation material 72 is lowered since the temperatures of hotter upper surface interfacing the air in the roof space 22 and the lower inner surface interfacing the living space 48 is reduced. Flange 38 prevents the denser, cooler air settling in the lower eave trough 71 where it would otherwise remain and be of no value.

In operation, the ventilation system vents increased quantities of the hottest air in the roof space 22 out through the top vent 10 proportionately as the roof space 22 temperature increases, so drawing in more dense cool air through the intake vents 34 and thus reducing the rate of temperature increase and heat transfer into the living space 48. In winter, or during cooler periods, this action also means that less air displacement will occur, so assisting the heating of the living space 48 by not lowering the temperature above the ceiling 32 or the ceiling insulation 72, thereby not significantly increasing the temperature gradient or heat transfer from the 900103, !MWSPE.011 ,roof.spe, 1 1 6 living space 48 at such times.

The ventilation system herein described improves the thermal environment of a living space 48 by overcoming the inherent constant undesirable parameters of insulation materials or thermal barriers of any type (including air specified by Heat Transfer Physics), so achieving more desirable and uniform comfort levels all year around in living space 48. In winter or colder periods the minimal, reduced air displacement advantage provided by this ventilation system still serves to reduce problems encountered associated with formation of condensation in roof space 22 either from ambient air or from kitchen, laundry, bathroom or other exhausts into roof space 22.

The inlet vents 34 would normally, where the structure permits in practice, be located under the eaves 42, so taking advantage of the more dense cooler air from this area, as it would be likely to be in shade. In any event, the air in the roof space 22 would be kept to approximately the ambient temperature of the air surrounding the dwelling 40, or possibly a little higher due to the instantaneous heating effect of the roof 30 with which it is either in contact, or from which it receives radiant heat. Certainly, the temperature would be far lower than the superheated temperatures of an unvented roof space 22.

The fire valve damper assembly 70 of Fig. 2, comprises a copper wire 56, the top end of which is soft soldered to the'centre of the flat top section of hood 12 of top vent through a hole which is sealed by solder and the crosssection of wire 56.

30 Copper is preferably selected for wire 56 in part due to its thermal conductivity and corrosion resistance together with metallurgical and other physical properties, but other suitable materials could be used. The valve damper component 24 of fire fuse assembly 20 is a close fitting circular disc relative to the inside diameter of tube 14. This allows no appreciable passage of air through tube 14 following destruction of the self-destructing fire fuse. component 28 (Fig. Valve damper 24 is constructed of flat galvanized iron of about 16 standard wire gauge to i 11 nit j_ .rr*niLI, -7provide the mass required together with corrosion resistance provided by the sacrificial zinc. A small central hole 62 in valve damper 24 locates around the slightly tapered stem 64 or firefuse 28.

The destructable fire fuse component 28 is specifically designed metal alloy of low melting point. To ensure survival of component 28 in the hottest non-fire environment in the roof space but low enough to self-destruct almost immediately should fire occur. The slightly tapered section of shank 64 of fire fuse 28 ensures correct holding and location of valve damper 24. The large surface area 60 of fire fuse 28 provides increased surface area to detect fire in conjunction with the heat collector action and location of valve damper 24 and wire 56 so optimising reaction time in the event of fire.

The self-destructive fire fuse 28 is attached to the copper wire 56 by means which ensure valve damper 24 will fall into the closed position irrespective of the mounting angle of vent 10, through central hole 66.

In use, the high temperatures associated with a fire will cause the destruction of fire fuse 28. Valve damper 24 will drop down to close tube 14, thereby cutting off the flow of air therethrough. This will at least reduce the inward flow of air through inlet vents 34 (Figures 3 and 4).

It can be seen that warmer or hotter air is vented from roof space 22 via the top vent component of the ventilation system, which as a consequence of this displacement draws in cooler air via the inlet or eave vents which allow the 9denser, cooler air to flow onto and across the upper surface I900103,!MWSPE. ,roof.sp, 7X 900 l34!MWSPE011roofspe, a; i i

SI

:I 7a of the ceiling or ceiling insulation. As a consequence of this, the temperature which otherwise would be present at this interface is reduced, resulting in lesser amounts of heat transferred to the cooler or living space side in summer or hot periods as the temperature gradient is reduced.

Living space comfort all year around is improved by the use of the present invention as it allows the utilization of lower, cheaper thermal resistant insulation which now improves living space comfort and is more desirable in achieving this than hitherto use of higher thermal resistant 11 1.1

I.'

U

PK~

Th 900103, !MWSPE.011 ,roof.spe, 1 "Mo 11

I

~i1 it 8insulating materials which restricts, due to the small temperature difference or gradient between this and the living space cooling in the cool of the evening as a result of the fixed characteristics of all insulation material.

5 The present invention is ideally suited to the Australian environment, as in most areas of Australia the significant thermal extreme relates to the higher temperature in that the external to internal temperature difference is much greater than in the cooler periods where such temperature difference is very much less, relative to desired internal comfort temperature desired.

In relation to summer heat it is stressed that when the external shade temperature reaches in excess of 30 C to 40 C the confined unvented roof space area will be at a temperature of from 50 0 C to 140 0 which over a large ceiling area represents a major problem due to the great temperature difference or gradient, and is thus a handicap to living space comfort.

Obviously the air flow or displacement should be a maximum during hot weather when the temperature in the area to be ventilated is high, but just as clearly the ventilation should be much less when the temperature in the area to be ventilated is lower. The present invention achieves this by utilizing the temperature at the time so the rate of displacement is directly controlled without mechanical regulating means.

The ventilation system of this invention achieves conservation of resource and exhaustable or manufactured energy while improving the comfort and temperature uniformity desired. Further, the ventilation system conserves exhaustable and manufactured energy required should some means of air conditioning still be desired for reasons of further reduction of temperature and/or humidity, filtering of pollen or other particulate matter, or vapour reduction, from the prevailing conditions. This conservation results as a consequence of the cooler living space achieved by the present invention, thus less heat requires less pumping or removal, so less exhaustable energy is consumed in reaching the desired objective.

4-- 9 Further objects of the invention are to improve the utilization of lower rated insulation which as a result of the present invention will provide improved living space comfort than possible prior.

A still further object of the present invention is to direct the cooler induced air drawn through the eave or intake vents by the action of the passive displacement resulting from venting the higher temperature air out of the outlet or top vent(s) from the roof space, so providing a layer of the denser or coolest air onto the ceiling or ceiling insulation air interface thereby minimising the o temperature difference or gradient which results in less 0.heat transfer into the living space.

A still additional object of the present invention is 15 incorporation of retaining means and air flow fire valve system. The retaining means will self-destruct at a temperature associated with fire, the venting, or causation of upward draft and drawing of air to sustain a fire in the confined space or structure is avoided by the automatic closure of a fire damper or air flow valve. This is a safety feature unique to the present invention consisting of components and materials of construction not prone to deterioration and having no intrinsic moving parts.

Still another object of the present invention is its intrinsically simple method and means of operation together with simple design inexpensive manufacturing cost, rugged construction, efficient operation and ease of installation, compatability with roofing materials and neat appearance, in part obtained by the inclusion of the lead flashing strip.

The entire contents of the complete specification lodged with Australian patent application no. 34663/84 is hereby imported into this specification and form part of the disclosure of this specification.

The claims form part of the disclosure of this specification.

Claims (4)

1. A passive roof space ventilation system for a building having eaves, including an air outlet adapted to vent relatively warm air located in said roof space from said roof space to the atmosphere, and an air inlet located in use at the eaves level of said building, through which air inlet relatively cool external air is adapted to flow to displace said relatively warm air vented by said air outlet, said air inlet including a duct defining an air passage, said duct having an air entry end and an air exit end, said air entry end being adapted to be located, in use, at said eaves level, said air exit end being adapted to be located, in use, at a higher level in said building than said air entry end and at a level such that it protrudes into said roof space and\such that said relatively cool external air passing through said duct and exiting therefrom at said air exit end will pass across and above a substantially horizontal interface between said roof space and a living space of said building, said air outlet being located, in use, at a higher level in said roof space than said air inlet.

2. A passive roof space ventilation system according to claim 1, wherein said air outlet includes a generally tubular member, there being a portion of said tubular member which allows the passage of air therethrough, but which obstructs the passage of objects.

3. A passive roof space ventilation system according to claim 2, wherein said tubular member has a cap, and further has flashing associated with the lower portion thereof, for jbspe.OOl/boundy 90 6 27 1 I I 11 securement of said air outlet to a roof.

4. A passive roof space ventilation system according to any preceding claim, wherein said air inlet includes a grating or screen to facilitate the passage of air therethrough but to restrict the passage of birds or animals therethrough. A ventilation system substantially as herein described, with reference to Figures 1, 3 and 4 or 1 to 5 of the accompanying drawings. 27 June 1990 SMITH SHELSTON BEADLE Fellows Institute of Patent Attorneys of Australia Patent Attorneys for the Applicant: BOUNDY VENTILATION SYSTEMS PTY LTD I c iir 001/boundy 90 6 27 -e 1