US20250052436A1

US20250052436A1 - Negative Pressure Envelop for Controlled Environment Rooms

Info

Publication number: US20250052436A1
Application number: US18/231,344
Authority: US
Inventors: Dan Lehrmann
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-08-08
Filing date: 2023-08-08
Publication date: 2025-02-13

Abstract

A room insulation system, for preventing leakage of contaminants from an insulated room to its surroundings and/or from the surroundings into the insulated room, the insulated room being enclosed by any of a floor, a ceiling and one or more walls, the system comprising—an inner panel, disposed parallel to, and a given distance from, a corresponding floor, ceiling or wall, forming an insulation space between them, andan air extraction system, including a fan and a filter;wherein the insulation spaces are fluidly interconnected, to form a Negative Pressure Envelope (NPE),the intake port of the air extraction subsystem is fluidly connected to the NPE and the exhaust port of the air extraction subsystem is fluidly connected to the atmosphere andwherein the air extraction subsystem is configured and operative to extract air from the NPE into the atmosphere while maintaining an air pressure within the NPE substantially below the atmospheric pressure and the air pressure within the insulated room.

Description

FIELD OF THE INVENTION

The invention generally addresses insulated- and controlled environment rooms and particularly rooms that need two-way isolation.

BACKGROUND

In various facilities there exists an insulated room (sometimes also known as clean room or controlled environment room), namely a closed room whose inside air is isolated from that of adjacent rooms and the atmosphere so that any exchange of air between them is only through special filters or other processing means. Examples of an insulated room include—

- an operating theatre in a hospital, where the air must be sterile;
- a so-called clean room in a semi-conductor wafer fabrication plant, where the air must be clean of dust and other particles;
- various medical and biological laboratories, where the air must be sterile and/or clean of dust and other particles or where the air is contaminated and must be prevented from leaking to the surrounding.

Some insulated rooms may actually be halls, vestibules, aulas or other inner spaces. In some cases the insulated space may be more than a room—e.g. a section of a building or an entire building; the present invention is applicable to such a space as well and thus it should be understood to be included in the term “room”.
To eliminate as much as possible the infiltration of uncontrolled air, clean rooms must be designed and built as airtight chambers so that no air will infiltrate into the room or from the room, to adjacent spaces. It is difficult to completely achieve this goal as there generally are many cracks and tiny holes in the walls and ceilings through which air can infiltrate the room. Furthermore there are typically in such a room various devices that need connection (e.g. electrical, fluid or gaseous) with spaces outside the room and thus wires, cables, pipes and ducts crossing the walls or ceiling may jeopardize the insulation integrity of the room. Sealing means at such crossing points, to maintain room integrity, are prone to failure, due to wear and/or mishandling.
For this reason, clean rooms are usually maintained at a positive pressure relative to adjacent spaces, thus preventing contaminated air from infiltrating into it. However, in some cases it may not be possible to achieve positive pressure in the clean room. Furthermore, certain clean rooms, such as those in which cytotoxic drugs are handled, there is an added requirement that air from inside the room also not leak out into the environment. Such a requirement would call for keeping the room at a negative pressure relative to adjacent spaces. This contradicts the usual positive pressure requirement in order to prevent contaminated air infiltration from outside and thus dramatically exacerbates the problem of effective insulation.
Thus there is a need for means to prevent air leakage both ways—from the insulated room towards surrounding spaces and from the surrounding spaces into the insulated room.

SUMMARY OF THE INVENTION

The present invention solves the problem of preventing air leakage both ways between an insulated room and adjacent spaces (thus avoiding both leakage and infiltration of contaminated air to or from the insulated room) by surrounding the room with a so-called Negative Pressure Envelop (NPE), which is a space in which the air is maintained at a substantially lower pressure relative to the atmosphere as well as relative to the air inside the insulated room.
A typical insulated room is enclosed by structural elements, such as a floor, a ceiling and walls. In some configurations of an insulated room according to the invention, one or more of these elements is constructed as a pair of mutually parallel panels, a given distance apart; in some other configurations, an inner panel is added, on the inside, to one or more of such existing structural elements so as to be parallel thereto and at a given distance therefrom. The space between each such inner panel and the corresponding outer panel or structural element forms a so-called insulation space and is nominally insulated from the space inside the room, as well as from spaces outside the room (except for possible cracks and unsealed passageways, discussed in the Background section).
Any one of the thus formed insulation spaces may be configured as an NPE, as explained below. Preferably, however, a plurality of insulation spaces surrounding the room is in fluid communication with each other—to form a single NPE.
As mentioned above, the air pressure inside the NPE is maintained at some given value, appreciably below atmospheric pressure and the pressure inside the insulated room. As a result, any air that leaks from the surroundings through an outer panel or wall (which air may carry dust or other contaminants) into the NPE will not proceed through the inner panel to infiltrate the insulated room, because of the higher pressure prevailing there; at the same time, any air that leaks from the insulated room through the inner panel (which air may carry toxic materials or other contaminants) into the NPE will not proceed through the outer panel or wall to the surrounding spaces. Thus all contaminants-whether from the surroundings or from inside the insulated room—that leak through the respective walls, floor or ceiling will automatically be captured in the low-pressure NPE space and may be filtered out by a suitable filter-preferably while being extracted out to the atmosphere.
In some configurations of the system according to the invention, the low pressure within the NPE may be maintained by means of an air extraction system, having an intake port in fluid communication with the NPE and an exhaust port in fluid communication with the atmosphere. The air extraction system includes a fan and preferably a filter and is configured and operative to draw air from the NPE, to possibly filter out any contaminants therein and to exhaust it to the atmosphere. The operation of the fan is controlled to maintain the desired low pressure within the NPE and preferably such that the rate of flow out of the exhaust port is equal to the total rate of air leakage from inside the room and from outside space into the NPE.
The desired low pressure in the NPE may be maintained under control of a controller, electrically connected to the fan and to a pressure sensor placed inside the NPE.
More specifically, the invention is of a room insulation system, for preventing leakage of contaminants from an insulated room to its surroundings and/or from the surroundings into the insulated room, the insulated room being enclosed by any of a floor, a ceiling and one or more walls, the system comprising—

- at least one inner panel, disposed parallel to, and a given distance from, a corresponding one of said floor, ceiling or wall, forming an insulation space between them, and
- an air extraction system, including a fan and a filter and having an intake port and an exhaust port;
  wherein one or more of the insulation spaces are fluidly interconnected, to form a Negative Pressure Envelope (NPE),
  the intake port of the air extraction subsystem is fluidly connected to the NPE and the exhaust port of the air extraction subsystem is fluidly connected to the atmosphere or any other surrounding space and
  wherein the air extraction subsystem is configured and operative to extract air from the NPE into the atmosphere while maintaining an air pressure within the NPE substantially below the atmospheric pressure and the air pressure within the insulated room.

The invention also contemplates an insulated room, structured and operative as described above.
The invention also contemplates a method for preventing leakage of contaminants from an insulated room to its surroundings and from the surroundings into the insulated room, by constructing and operating it as described above.

LIST OF ILLUSTRATIONS

The invention will be described in detail with reference to the accompanying drawings, wherein—

FIG. 1 is a schematic drawing of a typical configuration of an insulated room according to the invention;

FIG. 2 is a schematic drawing of another configuration of an insulated room according to the invention that includes an air refreshing- and filtering system.

DETAILED DESCRIPTION OF TYPICAL EMBODIMENTS

FIG. 1 depicts schematically the structure of an exemplary embodiment of a two-way insulated room according to the invention.
An inner chamber 2, enclosing an inner space 5 (together constituting the insulated room proper) is disposed within an outer enclosure 1. The outer enclosure 1 typically consists of a floor 1B, an outer wall panel 1A and a ceiling 1C and may be part of the building structure. The inner chamber 2 typically consists of an inner wall panel 2A and a hanging ceiling 2C. The floor of the inner chamber 2 may share the floor 1B of the enclosure, assuming the floor to be impervious to air; in other embodiments an inner floor (not shown) may be suspended above the floor 1B, forming a space therebetween. The space between the ceiling 1C and the hanging ceiling 2C constitutes a plenum 3. The inner wall panel 2A and the outer wall panel 1A form a wall space 4 between them; in some embodiments the two panels may be parts of a structured wall (e.g. a so-called dry wall). Each of these spaces—the plenum, those between the wall panels and possibly that under the suspended floor—is an enclosed space and will be referred to as an insulation space. Each insulation space may be regarded as an NPE, but preferably (as in the illustrated example) some or all of the insulation spaces are fluidly interconnected and together form the NPE space.
Also shown in FIG. 1 is an air extraction (or exhaust) system, including a fan 11, having an exhaust port 17, a filter 12 and an intake port 18. It is seen to be disposed in the ceiling 1C (but may also be disposed in a wall) with the intake port 18 protruding into the NPE space, e.g. plenum 3. The fan 11 is configured to draw air from the NPE, through the filter 12, and to blow it through the exhaust port 17 into a surrounding space-preferably the atmosphere or an external air purification system. With the cooperation of a pressure sensor inside the NPE and a controller (not shown), electrically connected to the fan, the fan is further configured to maintain a desired negative pressure within the NPE, as is known in the art.
As can be clearly seen in FIG. 1 , air that leaks from the chamber space 5, through say inner panel 2A (path 7), as well as air that leaks from the outside, through say outer panel 1A (path 6), to the space 3 or 4 of the NPE will both be captured by the lower pressure therein. It will be exhausted, together with any contaminants carried by it, via the intake port 18, by the action of the fan 11, continuing through the filter 12, where the contaminants are extracted, to the atmosphere.
To summarize, in the configuration of FIG. 1 , the Negative Pressure Envelope consist of the spaces within the hollow walls 4 and the ceiling plenum (3). It should be understood that more generally, the term hollow walls stand for a space between two boards or panels or walls in any building configuration known in the art.
It is noted that in some other embodiments there may be a plurality of non-interconnected NPE spaces, each with its own exhaust system.
Conventional insulated rooms are usually also equipped with a system to actively filter and refresh the air within them. An embodiment of an equivalent insulated room according to the invention, illustrated schematically in FIG. 2 , is otherwise similar to that of FIG. 1 , but includes an example of such an air refreshing and filtering system-namely one that renders the chamber to be a so-called “Controlled Environment Room”. The air refreshing and filtering system basically consists of an air-supply sub-system 20 and an air exhaust sub-system 30.
The air-supply sub-system 20 comprises—

- an air handling unit 29, which may include a conventional air-conditioner (with cooling and/or heating) and/or a filter, as well as air propulsion fans;
- a room air supply duct 23;
- a room air return duct 22; and
- a fresh air intake 24, with a filter 25.

The air exhaust sub-system 30 comprises—

- a room air exhaust duct 32;
- an exhaust filter 33; and
- a fan 31, directing exhaust air to the atmosphere.

It is noted that the air refreshing and filtering system, shown in FIG. 2 and described hereabove, is a known technology and acts independently of the air extraction system, connected to the NPE, as disclosed in the present paper.

Claims

I claim:

1. A room insulation system, for preventing leakage of contaminants from an insulated room to its surroundings and/or from the surroundings into the insulated room, the insulated room being enclosed by any of a floor, a ceiling and one or more walls, the system comprising—

at least one inner panel, disposed parallel to, and a given distance from, a corresponding one of said floor, ceiling or wall, forming an insulation space between them, and

an air extraction system, including a fan and a filter and having an intake port and an exhaust port;

wherein one or more of said insulation spaces are fluidly interconnected, to form a Negative Pressure Envelope (NPE),

the intake port of the air extraction subsystem is fluidly connected to the NPE and the exhaust port of the air extraction subsystem is fluidly connected to the atmosphere or any other surrounding space and

wherein the air extraction subsystem is configured and operative to extract air from the NPE into the atmosphere while maintaining an air pressure within the NPE substantially below the atmospheric pressure and the air pressure within the insulated room.

2. An insulated room, structured as an enclosure having any of a floor, a ceiling and one or more walls, comprising an air extraction system, including a fan and a filter and having an intake port and an exhaust port;

wherein any of said floor, ceiling or wall is structured as two mutually parallel panels, a given distance apart and defining an insulation space between them,

wherein the intake port of the air extraction subsystem is fluidly connected to the NPE and the exhaust port of the air extraction subsystem is fluidly connected to the atmosphere or any other surrounding space and

3. The insulated room as in claim 2, further comprising an air refreshing- and filtering system in fluid communication with space inside the room and with the atmosphere.

4. A method for preventing leakage of contaminants from an insulated room to its surroundings and from the surroundings into the insulated room, the insulated room being enclosed by any of a floor, a ceiling and one or more walls, the method comprising—

providing at least one inner panel and disposing it parallel to, and a given distance from, a corresponding one of said floor, ceiling or wall, to form an insulation space between them;

optionally fluidly interconnect a plurality of the insulation spaces;

configuring any one insulation space or said fluidly interconnected plurality of insulation spaces into a Negative Pressure Envelope (NPE), wherein the air pressure may be maintained below the atmospheric pressure;

providing an air extraction system, including a fan and a filter and having an intake port and an exhaust port and disposing the air extraction system so that its intake port is fluidly connected to the NPE and its exhaust port is fluidly connected to the atmosphere or any other surrounding space;

operating said fan so as to extract air from the NPE into the atmosphere and to maintain the air pressure within the NPE substantially below the atmospheric pressure and the air pressure within the insulated room.

5. The room insulation system of claim 1, wherein the air extraction system further includes a pressure sensor, disposed within the NPE, and a controller, electrically connected to the pressure sensor and to the fan,

the fan, the controller and the pressure sensor being cooperative in said maintaining of the air pressure within the NPE.

6. The insulated room of claim 2, wherein the air extraction system further includes a pressure sensor, disposed within the NPE, and a controller, electrically connected to the pressure sensor and to the fan,

7. The method of claim 4, further comprising—

providing an air pressure sensor and a controller, electrically connecting the controller to said sensor and to said fan and

causing the controller to control the operating speed of the fan according to a signal from said sensor.