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Staircase Design of High-rise Buildings Preparing against Fire

Staircase Design of High-rise Buildings Preparing against Fire

| On 26, Apr 2001

TRIZ Paper: TRIZ/USIT Case Study
Toru Nakagawa (Osaka Gakuin University)
August 7, 15, and 24, 2000 [in Japanese]
English translation by Toru Nakagawa on Aug. 24, 2000 and on Feb. 7, 2001[posted on Aug. 24, 2000 and on Feb. 28, 2001]

Preface (Toru Nakagawa, Aug. 15, 2000)[translated into English and posted here on Aug. 24, 2000]

I wrote this paper during my work of Japanese translation of Yuri Salamatov’s TRIZ textbook <> “TRIZ: The Right Solution at the Right Time”, being stimulated by one of its exercise problems. Problem 43 of the textbook describes the difficulty of escaping from and rescuing people from fire of modern high-rise buildings, and shows a design of Vilchinsky’s ‘gravitational elevator’ for urgent evacuation seeking for your further improvement. While working on the brushing up of our Japanese translation, I was thinking that we should have some more basic and essencial improvement for preparing against fire.

Note: For a breif introduction to TRIZ and USIT, see (D) of this paper.

Many years ago I saw an American movie “Towering Inferno” (1974) on TV. It delt with a fire of a skyscraper and gave a shock to the world. On fire, the elevators stopped working, staircases got fire and smoke due to the chimney effect, and people were confined in the top floor lobby while the burning fire was getting closer. I thought, among many other people, that we should have some secure ways to safely escape from fire of high-rise buildings.

While doing the translation work, I thought that we should, first of all, keep the staircases as the safe evacuation routes and that we should avoid the staircases from becoming a chimney in case of fire. Then I came up with the simple idea that for preventing the chimney effect we should just have big windows on every floor of the staircases. I wrote it down on a small piece of scratch pad at hand. It was on August 1st, this year.

The idea written on the pad gradually grew in my mind, and I became confident that the idea of setting large openings on every floor at the starcases is simple yet very effective solution to this problem. So I started to write down my idea in the morning of August 7 at home during the summer vacation. Soon after starting, I began to use the format of “Description of an Invention” which we used at Fujitsu Labs for showing inventive ideas to patent specialists for their help. Following the format, I wrote down my idea with a numbr of small goes and backs; it took me about six hours for the work. The “Description of an Invention” is posted here in Section (B).

During this writing work, I considered various points and wrote them down in the manuscript. If you ask me “Did you use TRIZ and/or USIT process?”, I feel some difficulty to answer. I did not use formal processes of TRIZ/USIT, but I certainly used many principles and thinking ways of TRIZ and USIT together with many other experiences and background knowledge in my mind. I just used all my ability during thinking and writing, without explicitly following any single methodologyexcept the format itself. Even so, the following two points are clear:

Fist, in defining the problem, I chose “To keep the staircases safe for evacuation preventing from becoming like a chimney in case of fire”. This problem definition has determined the whole problem solving process for the present work. I feel I used the USIT way of thinking for this problem definition process.

Second, I solved the problem with the final solution: “In ordinary times, the staircases are convenient and confortable, located inside the building, and in cases of fire, they are wide opened to outside, serving as the safe evacuation routes and as the bases for firedistinguishing and rescue activities.” This solution clearly reflects the TRIZ’ Separation Principle in time. During solving, I had clear recognition of a technical contradiction (between convenience/confortability and fire-preparation) and a physical contradiction (i.e., staircases should be located inside and simultaneously outside the building) of this problem. And I was also well aware of my using the TRIZ way of solving the contradictions. I became aware of these points right after starting the description work.

After finishing the ‘Description of an Invention’, I thought this solution could become a patent. So I searched the patent database of Japanese Patent Office on the internet. Using the keywords ‘evacuation AND staircase’, I got 56 hits of Japanese patents. Quickly reviewing the patent abstracts, I found nothing relevant. Furthermore, I have never seen buildings whose staircases are designed in the sense of the present idea.

It was certainly of some interest for me to obtain a patent on this idea, if possible. But I declined to do so, considering the tedious work of finding some appropriate collaboration company for filing the patent and of fighting in courts to realize the benefits of the patent. Moreover, if I should seek for the possibility of patent, this idea would have to be kept secret for a certain period, and would be much delayed and limited in being realized in society. So having thought for a week, I have decided not to try to file a patent on this idea but to publish it as widely as possible so as to be realized in a huge number of buildings in Japan and in the world. Fortunately, I am in a position to be able to publish this idea freely without requesting any permition from others.

For this purpose, I am posting the present paper publicly in my Web site “TRIZ Home Page in Japan”. As a case study of TRIZ/USIT, this page includes the following three parts:

(A) The beginning and background of the present idea (Aug. 24, 2000)
(B) Description of an Invention: ‘Staircase design of high-rise buildings preparing against fire” (Aug. 7, 2000)
(C) The thinking process and the influences of TRIZ/USIT (Aug. 24, 2000)

With these three parts, the present author wishes to make clear how the TRIZ/USIT methodology has been actually used in this case of study.

The present author also wishes that this paper should be read as widely as possible in the world to prepare against fire casualty.

[Editor’s Note (Toru Nakagawa, Feb. 28, 2001): The body of the present page, i.e. (A)(B)(C)(D), were translated into English on December 22, 2000 and are posted here on Feb. 28, 2001. The present work will be presented at the TRIZCON2001 to be held on March 25-27, 2001.]

Top of this page A. Beginning & background B. Description of an Invention C. Actual Thinking Process D. Introduction to TRIZ & USIT

(A) The Beginning and Background of the Present Idea (Aug. 24, 2000)[English translation by Nakagawa, Dec. 22, 2000 (posted on Feb. 28, 2001)]

1. Exercise Problem in Salamatov’s TRIZ Textbook

As described above in the Preface, the present work happened to start during my work of translating Yuri Salamatov’s TRIZ textbook from English into Japanese. This textbook explains a wide range of aspects of TRIZ in a systematic way, and the translation work gave me a precious chance of studying the textbook very closely. Among many problems in the textbook, Problem 43 (pp. 66-67) is read as follows:

Problem 43. New buildings are getting taller, 20-, 30-, 50-, 100-storied buildings appear. But survival craft remains practically with no change. The longest telescopic ladder available today only reaches the 12th floor. At the same time one can only rescue people through windows, because staircases and elevators turn into gigantic chimneys. Fire can spread very quickly turning a skyscraper into a burning candle. You should not count on the rescue service with their ropes, ladders, automatic elevators and even the hi-tech ‘flying saucers’, or mini-helicopters manufactured now in Japan. There should be one simple and reliable method of urgent evacuation from a building on fire.

A ‘rescue hose’ was invented. It was made of elastic cloth and armoured with glass fiber. When the hose is not used, its diameter is a bit smaller than the average thickness of man. One can regulate fall speed by expanding one’s elbows and moving one’s knees together. Unfortunately, not everyone can use this bright idea. The system cannot be recommended to elderly people and children even after long training.

The system was improved by G. Vilchinsky (Soviet Patent no. 1 024 098).

Gravitational elevator, invented by G. Vilchinsky.
[When a person gets on,] Elastic chambers (1) shrink, driving excessive pressure through the pipe line (2) into the reservoir (3). The piston (4) moves, compressing the spring (5). When a person exits the receiving chamber (6), the spring brings the piston to its initial position, air enters the crushed chambers (1) expanding them.

We suggest that you improve it further: the process of technical system development is endless. What is bad about the system? Try to make it more effective, decrease it in size and mass, add new functions to it, for the fire may not happen at all the system will be out of use.

The introduction part of the Problem is written vividly to urge readers’ attention. But the device for urgent evacuation, especially the one illustrated in the above figure, does not seem to work effectively, even reading the explanation many times. “Something is wrong in this idea”, I have had such a vague impression for over a year since I read it first.

2. Background Knowledge and Experiences

My background knowledge about the fire of high-rise buildings is at the level of common sense but still large. You readers would have similar or even much more knowledge. Some of my background knowledge reminding me with strong impression are described below:

(1) American movie “Towering Inferno” (1973): I saw this movie on TV many years ago. A skyscraper in US has got a fire. Sprinklers do not work well. The fire extends through the ducts towards upstairs much more rapidly than expected. People who try to go down with the elevator are locked in between the stories and have to get out of it by breaking the top of the carrage. Staircases get flame and smoke like in a chimney and can not be used for escaping. A fire-man who goes up in the emergency staircases has nearly been caught by the flame. Many people are forced by the fire to go up to the roof top. Helicoptors are not accessible to the roof top because of the heat and strong winds induced by the fire. The water reservoir on the roof top has been broken by the explosives and it has extinguished the fire finally. — This movie gave a big impact on people around the world. It has vividly described possible situations when a skyscraper gets fire. What sort of solutions can we find out to this kind of disasters?

(2) Emergency devices for going down: My office at the university is located on the 4th floor of an eight-story building. An emergency device, named Slow-Down, is equipped inside the window at the rounge near the elevator hall. In case of emergency, we are supposed to put its belt around our waist and go down by hanging on a rope. I have read its instruction written on the box several times, but have had no experience of using it. Except for the emergency cases, no one should handle it, thus no one in the building has made an exercise on it. In case of a real fire, and of having no other ways, we will have to use it in a “do-or-die” situation. We recall that recently during an on-air TV program for demonstrating the usage of this kind of device, a woman TV caster accidentally dropped from fifth floor and seriously wounded, because the end of the rope slipped from the fixed furniture. I know some other emergency escape devices like a tube, in which we slide down. It must be terrifying for us to use it from 10th story of a building. Is it still useful to slide down from 20th story of a building?

(3) Staircases in high-rise buildings: In tall buildings, having several or more stories, it is common to use elevators for going up and down in ordinary situations. In such buildings, it is sometimes difficult for us to find the staircases for going up/down to the adjacent floor. Staircases are built at a place almost hidden, and the fire-door to them are closed with the sign of ’emergency exit’. Using such staircases, I feel a strange atomosphere as if someone regards me going through a confidencial place like a theft. In most cases, such staircases do not have windows and look like in a warehouse. Staircases in hotels are more or less the same.

(4) In Japan, there was a disastrous fire at the Hotel New Japan in 1978. Many hotel guests were burned without finding their ways out. Newspapers reported that a man escaped from the fire by traversing on the outside wall from the windows to windows. Later, I was surprised to meet one of my old university classmates who declared that he himself was the person.

(5) Buildings with three, four stories often install emergency staircases outside on the side walls. The emergency exit doors can be opened only from inside. But the emergency exits often become the weak point in preventing from thefts, because some people living in the building may leave the doors unlocked for various reasons, e.g. making shortcuts, coming back after the closing time, etc.

In addition, concerning the chimney effects, I have various background knowledge. During my childhood, I burned woods for heating bath water; thus I learned the effects of chimney and wind for burning. I have read and seen industrial problems for burning in furnaces and for cooling electrical equipments by introducing natural air flow using the chimney effect, etc. — By the way, I now notice that we have experienced a number of problems for introducing and intensifying the chimney effect but seldom experienced the problem for reducing the chimney effect.

3. Getting the Idea on the Problem

While reading the above mentioned Salamatov’s problem and examining the figure, I was thinking that this figure is not clear in its mechanism and this device would not work well. This thought was the initial point of the present work.

– Making the device as a vertical straight column, it would become a chimney just like the staircases. — At that time I thought so. But if the device is attached on the outside wall of the building, it may be avoidable from becoming a chimney, I now think.

– How many passenger carrages are installed in this device? There should be a carrage wherever people want to get on, while empty carrages should not block the passenger carrage to go down.

– How should we do after one person gets off? We should lift up the carrage for rescuing the next person. — We may install many carrages in a loop-form way, I now think.

– The idea of reserving and reusing the air pressure does not seem to work.

“The idea in this figure seems too much sophisticated to work. Even if it works, no body would use it in practise. We should reconsider this problem in a more essential way, I thought.

Elevators should not be used because of their risks of being stopped and being locked in. Then, we should better use the staircases, because we can act there for ourselves and by our own decision. We should better make the staircases more useful in case of fire emergency. But staircases could not be used due to the chimney effect, … Then, we should just prevent the staircases from becoming a chimney!”

When I came up with the idea of “preventing the staircases from becoming a chimney”, the solution to it was trivial. If we make large openings in the staircase, the chimney could be interrupted. Even though we have a sequence of staircases from the ground to the top, we should just put large openings on every story of the staircases. Then the staircases would not become a chimney, by breaking the air flow and smoke at every story. This idea is based on a simple knowledge which pupil in elementary schools or junior highschools learn in classes.

(B) Description of an Invention: “Staircase Design of High-rise Buildings Preparing against Fire”(Aug. 7, 2000) [English translation by Nakagawa on Dec. 22, 2000 (Posted on Feb. 28, 2001)]

1. Title of the Invention:

Design of staircases for high-rise buildings preventing the chimney effects in case of fire

2. Conventional Means and Their Problems

2.1 Application Areas of the Invention

The present invention concerns with the design of high-rise buildings with several or more stories, especially with the design and structure of such buildings taking prior consideration of emergency escaping means in case of fire and earthquake, and particularly with the design of staircase rooms of such buildings.

2.2 Conventional Means

As ordinary means to go upstairs or downstairs in high-rise buildings, (a) elevators, (b) escalators, and (c) staircases are widely used. As emergency means to go upstairs or downstairs for escaping in case of fire and earthquake, however, the elevators are usually prohibited to use and the escalators are not convenient even in operational cases, thus the staircases should make a major role.

Staircases for such emergency escaping are usually installed on the outside walls of buildings, because the staircases built inside the buildings would often become like chimneys by themselves. However, the staircases on the outside walls bring different problems of possible invasions and thefts in ordinary days. Thus staircase design should be considered to overcome these new problems as well.

From these points of view as emergency escaping route, the structure of staircases of high-rise buildings may be classified in the following categories:

(A) “Internal Staircases”: staircases built inside the buildings

(A1) “Non-separated Internal Staircases”:
Open staircases which are not separated from the rooms of the floor in the sense of fire protection.

(A2) “Separated Internal Staircases”:
Staircases which are separated from the rooms of the floor in the sense of fire protection and are formed as separated rooms by themselves.

(B) “External Staircases”: staircases built or attached outside the buildings

(B1) “Emergency-Only External Staircases”:
External staircases which should be used only in case of emergency and are prohibited to use in ordinary days by locking the door between the staircase and the floor room. The emergency-exit doors can be unlocked easily only from inside. The staircases are regarded as being outside the buildings in the sense of theft and invasion protection.

(B2) “Free-Access External Staircases”:
External staircases which are used every day as ordinary passage accessible freely from outside the buildings. From the viewpoint of theft and invasion protection, the staircase and its connected passage are regarded as being entirely outside the buildings. Entrances to the rooms of each floor are regulated by locking the doors individually. This design of staircase is often used in residential apartment buildings of low and high stories.

Besides the ordinary means mentioned above, there can be various means for rescuing people who are left at higher stories of a burning building. They include emergency descending devices, fire engines with long telescopic ladders, helicopters, etc. These emergency means, however, are to be used for rescuing people who have failed to escape safely at the earlier stages of fire. The present invention intends to make larger chances of escaping from fire safely at the earlier stages.

2.3 Problems of the Conventional Means

High-rise buildings have been built higher and larger and in ever increasing numbers. Once such a building gets fire, the fire spreads not only horizontally at the floor but also vertically to the neighboring floors. The fire spreads upstairs through ducts for air-conditioning and pipes and cables, and through vertical spaces for elevators, escalators, and staircases due to the chimney effects. The speed of upward extension of the fire is often surprisingly fast, and it becomes difficult to rescue people who are left at the floors higher than the burning floor.

In case of fire or earthquake, it is the general policy of today to prohibit the usage of elevators for emergency escaping. This is because the elevator may abruptly stop its operation due to some damage in the driving or controlling system and may confine people locked inside it, and because people in the elevator have a high risk of being exposed to heat, smoke, and toxic gases coming in due to the chimney effect of the elevator shaft.

Escalators may be operational at the initial stages of fire, but probably not when the damage of the fire spreads. Staying escalators can be used just like staircases, but are slippery and not so convenient.

Thus it has much significance in case of fire whether the staircases are available as safe escaping routes or not. If they are available and safe, people can make their own ways out for themselves judging the emergency situations. So let us examine the problems in staircases of each of the above mentioned categories.

(A1) “Non-separated Internal Staircases”:

At the floor where the fire starts burning, flame, smoke, and toxic gases can easily enter into the open staircase. Consequently the fire can quickly extend towards upstairs. Thus, this design of staircases is usually avoided in high-rise buildings. Apparently-open-style escalators and staircases at shopping floors of high-rise buildings usually have fire-doors or shutters installed to separate them from the floor rooms in case of fire.

(A2) “Separated Internal Staircases”:

In preparation against fire, this type of staircase are separated with firewalls from the rooms of the floor and are installed with fire-doors at the entrances to the inside passages. Being separated from the floor rooms, the staircases are built as separated rooms by themselves and forming a vertically-arranged sequence. This is the typical structure of staircases in today’s high-rise buildings. However, if the fire-door is not closed tightly at the burning floor due to some failure, defect, or damage, then enter flame, smoke, and toxic gases into the staircases and go upwards all through.

In today’s high-rise buildings, this type of staircases are often built in a somewhat hidden space near the elevator hall, and are built with solid walls often without windows. This closed structure may come from necessity of air-conditioning in ordinary days. However, the closed and vertical hollow structure of this type of separated staircases causes the chimney effects in case of fire.

(B1) “Emergency-Only External Staircases”:

This type of staircases are to be used only in cases of emergency. Thus the staircases are built with simple and humble structure, and are often maintained poorly. The management of locks of these emergency exit doors is often the problem concerning to the invasion and theft protection. The locks must allow to be opened easily and freely from inside at any time expecting the emergency cases, but must not be opened without keys from outside. If someone leaves an emergency door open for some reason, the problem of invasion and theft arises.

This type of staircases are usually built on the outside wall without cover; so they do not involve the chimney effects, and are not suffered from being filled with heat, smoke, and toxic gases. This is a big advantage as an emergency-escaping route. From the viewpoints of style and invasion protection, however, this type of staircases are rarely adopted in modern high-rise buildings.

(B2) “Free-Access External Staircases”:

The advantage of this type of staircases is similar to that of (B1); since its structure is not closed, it does not involve the chimney effects, and is not suffering much from flame, smoke, and toxic gases in case of fire.

Since this type of staircases are used every day and regularly and are freely accessible from outside, the means of regulating the entrance into the floor rooms must be provided. If the floors or the individual rooms are used or operated more or less independently by some limited number of people, they may be managed to lock separately. But such a locked-door system might be inconvenient if rooms at multiple floors are used by a large number of people such as those belonging to a business unit. Since the areas of staircases are outside the buildings, they are not air-conditioned and sometimes exposed to wind and rain.

Summarizing these analyses, we find the main problem is how to make compatible the two types of requests: they are the requests for convenience, comfort, and safety from invasion and theft in everyday ordinary situations on one side and the requests for availability, safety, and effectiveness in emergency cases of by fire. Generally speaking, the internal staircases of the (A1) and (A2) types are adapted primarily for the ordinary situations but poorly for the emergency situations. The external staircases (B1), on the other hand, is to be used only in emergency cases while leaving useless in ordinary everyday situations; thus it is regarded as an additive but not the main facility of the high-rise buildings. The (B2) type external staircases have much advantages as the safety means against fire, but seem to have limited applicability because they are uncomfortable and inconvenient in ordinary situations.

2.4 Tasks to Be Solved

Staircases of high-rise buildings have to be designed and built so as to be not only convenient, comfortable, and safely guarded for everyday ordinary use but also safe and secure as emergency escaping routes in cases of fire and earthquake. In particular, they must be designed not to cause the chimney effects in case of fire and not to get suffered from being filled with flame, smoke, and toxic gases of fire.

It is also desirable to have subsidiary functions that at the staircases people can stay safely on a temporary basis even during the fire, look around and judge the current situations of the building and fire, and moreover that the staircases serve the firemen and rescue team as their bases for carrying out their full activities.

3. Means to Solve the Problems

After the analysis of the problems as described above, we have obtained the following solution for the staircase design:

(1) To fulfill the convenience in ordinary time, the staircase should basically be a kind of ‘Internal Staircase’.

The staircase should be for every-day use, not exposed to wind and rain, comfortably air-conditioned, and safely guarded.

(2) The staircase should be of a ‘Separated’ type of ‘Internal Staircase’, in order to prevent the extension of fire and to ensure it as an emergency escaping route.

The staircase must be separated from the rooms of the floor with firewalls and fire doors.
Even if the rooms of the floor are burning, the fire should be kept from entering into the staircase.
The fire door should block the flame, smoke, and toxic gases, as surely as possible.
The staircase must be built with non-inflammable materials, which should not produce toxic gases in fire.
It is suggested to set a fireproof window in the fire door at a low position near the floor.
It may be recognizable as the emergency exit in the darkened room.
It will guide people towards the lower position.
Firemen and rescue team can look into the room without opening the fire door.
The window at such a low position will not be attacked with fire so much.

(3) In case of fire and earthquake, the windows of the staircase are opened widely.

This means that the Internal Staircase changes its structure into that of the External Staircase only in case of fire.
For this purpose the staircase must be located towards the outside of the building.
Opening the windows performs the role of eliminating the chimney effects. The Internal Staircase which was a hollow cylinder (i.e. like a chimney) from the bottom to the top inside the high-rise building now has the openings at every floor and effectively loose the structure of the chimney. With the elimination of the chimney effects, the staircase now plays less role of letting the fire extend towards upstairs.
The smoke and toxic gases getting into the staircase may go out through the openings, without densely filling in the staircase on the burning and the neighboring floors.
At the staircase people can breathe the fresh outdoor air. Thus people may be allowed to stay there safely for the time being even during the fire.

(4) The open windows and the halls of the staircase may be used as the entrance and action bases for fire-distinguishing and rescuing activities during the emergency.

The people escaping from fire and needing rescue can call help from there to the rescue team outside the building.
Devices for emergency exit may be equipped there.
The firemen and rescue team can get into the building through the open windows at the staircase (maybe with the help of a ladder or a helicopter).
It is suggested to make it possible for the escaping people to look around the outside walls of the building from the staircase.
This helps people understand the current situation better and escape from fire more safely.
To look around the outside walls, the staircase itself may be stuck out from the wall; but as an alternative, some concave mirrors may be set outside the staircase to see the walls (only in case of fire).

(5) The windows of the staircase should be able to be opened in case of fire remotely at the control center of the building.

The windows of the staircase may be opened by hand on site. But this hand operation may not be effective in case of emergency. So the windows should better be opened remotely at the control center.
The windows may be opened either on site or at the control center; they may be closed on site.
If any window of the staircase is opened by hand in ordinary situation, an alarm should be shown at the control center of the building.
The openings should better be made of transparent glasses, so that the people who use the building easily recognize them as the emergency openings.
The glasses of the windows should be reinforced so that once they break they are broken into small round pieces without the danger of injuring people.

In summary, the present invention proposes the solution that the ordinary “Separated Internal Staircases”, which have been used most widely for high-rise buildings, should be turned into the “Free-Access External Staircases” by opening the windows simultaneously in case of fire. This opening of the windows results in elimination of the chimney effects of the staircases, ensuring of the staircases as safe escaping routes, and serving the staircases as the basements for the escaping, firedistinguishing, and rescueing activities during the emergency cases of fire.

4. Examples of Application

(Not completed yet.)

5. Effects

(Not completed yet.)

6. Claims of the Patent Application

(Not completed yet.)

(C) The Actual Thinking Process and the Influences of TRIZ/USIT on It (Aug. 24, 2000) [English translation by Nakagawa, Dec. 22, 2000 (posted on Feb. 28, 2001)]

1. Problem Definition and the USIT Method

How I started to think this problem and obtained the initial idea is descrived above in (A). The process was done all in my mind quickly and intuitively; and it may be described somewhat more logically as follows:

First, the sentenses of Salamatov’s exercise problem are analyzed. Let us show the structure of the sentences more clearly by adding CRs, using indentations, and eliminating some details:

New buildings are getting taller, 20-, 30-, 50-, 100-storied buildings appear.
But survival craft remains practically with no change.
The longest telescopic ladder available today only reaches the 12th floor.
[In case of fire] one can only rescue people through windows,
staircases and
elevators turn into gigantic chimneys.
Fire can spread very quickly turning a skyscraper into a burning candle.
You should not count on the rescue service with their ropes, ladders, automatic elevators
and even mini-helicopters.
There should be one simple and reliable method of urgent evacuation from a building on fire.
A ‘rescue hose’ was invented.
Unfortunately, the system cannot be recommended to elderly people and children.
The system was improved by G. Vilchinsky.
We suggest that you improve it further.
Try to make it more effective, decrease it in size and mass, add new functions to it.

The logic inside this exercise may be shown more explicitly as follows:

High-rise buildings are increasing. (having 20 stories, 100 stories, etc.)
–> Means of preparing against fire are demanded.
–> We focus on the means of escaping and rescuing people from fire.
–> Escaping with ordinary means:

–> Escaping with elevators
=X No. Elevator may turn into a chimney.
[Risks of damage in control and drive.]
–> Escaping through staircases
=X No. Staircase may turn into a chimney.

–> Rescuing people by firemen and rescuing teams:

–> Rescuing with a telescopic ladder
=X No good for over 12 the floor.
–> Rescuing by the rescuing team (with ropes, ladders, helicopters, etc.)
=X Not dependable/available.
–> Rescuing through the windows

–> Means of emergency escaping

–> Emergency escaping with the ‘rescue hose’
=X No. Not applicable for everybody.
–> Emergency escaping with Vilchinsky’s ‘gravitation elevator’
=X No. Much room for improvement.
–> New means of emergency escaping is demanded.

As the result of the reasoning illustrated above, the exercise problem proceeds towards an improvement of the means of emergency escaping. But the future of such a device seems not bright enough.

So we should go back to the starting point of this problem and reconsider the solution for escaping and rescuing people from fire. We think it most important for us to escape or be rescued from fire in its early stage. This urges us to find some effective solution on the basis of ‘escaping with ordinary means’; it must be practical and widely applicable. Examining the reasons why such means were rejected above, we find it “because the elevators and staircases turn into chimneys in case of fire”. We should think over this reasoning again. “Do they necessarily become like a chimney?” “Is there any means of avoiding them from becoming a chimney?” This way of thinking was the key to the problem definition in the present work.

As described above, it is most important to think over the whole problem (i.e., ‘the means of escaping and rescuing people from fire’ in the present case) and to find the overall structure of the problem (i.e., ‘the problem system’) including various conventional approaches. The specific problem currently requested (i.e., “the improvement of Vilchinsky’s emergency escape device” in the present case) should be examined again in the perspective of the whole problem system.

This way of thinking corresponds well with the USIT method in its problem definition stage. USIT recommends to think the problem as a system. Sickafus advises to select such a problem that the solution to it can bring significant profit and to focus on the biggest and most essential issue in the problem. In the problem definition stage of USIT, these points are considered through the discussions in the problem solving team (and the guidance by the leader). As a result of such discussions, USIT often guides the team to much improve the initial problem definition by the person who brought the problem and to come closer to the essence of the problem.

Furthermore, in its initial stage of problem definition, USIT guides the team to consider and discuss: “What is the problem? What are the plausible root causes? What is the (physical) mechanism of the problem?” In the present case study, USIT has guided me to consider “Why escaping and rescuing people from fire is so difficult?” So it has made clear to me “Escaping from fire is difficult because elevators and staircases may become unavailable in case of fire.” Then I asked to myself “Why do they become unavailable?” and get the answer “Because they turn into a chimney”. Further I asked to myself “Then, why do they turn into a chimney? What is the physical mechanismof it?”, and I came to understand the problem of the staircase in the shape of a chimney, i.e. a tall hollow cylinder without openings. As a result of these series of questions, I have obtained the problem definition of the present case quite naturally and have come up with the initial idea very easily.

2. The Process of Drafting the ‘Description of an Invention’

The format of ‘Description of an Invention’ described above is used in Fujitsu for the documents to be prepared by the inventor to explain the invented techniques to get help from patent specialists for filing patent applications. It is almost the same with the essential part of the patent application form. Once the inventor write a document in this format, the specialists in patent department/patent agency can easily extend it and brush it up into formal patent applications.

The main items of the format are as follows:

1. Name of the invention
2. Conventional means and their problems
2.1 Application areas of the invention
2.2 Conventional means
2.3 Problems of the conventional means
2.4 Tasks to be solved
3. Means to solve the problem (i.e. explanation of the basic idea of the invention)
4. Examples of application
5. Effects
6. Claims of the patent application (draft)

In the present case, I started to draft the document directly on a PC with putting nearby the small piece of paper of the initial idea scratched a week ago. I wrote the document in the normal order of the above format. The actual process of drafting, however, went on back and forth many times. When I wrote several sentences or one or two paragraphs, I often noticed that the latter portion of the newly written part should be placed not in the current section but in the next section of the format. Thus I moved the latter portion to the next section and wrote some more extension in the current section. I had to repeat this kind of corrective work in the drafting.

The most important work in drafting was to write down the conventional means in a systematic way. I tried to write down my knowledge and experiences, i.e. those similar to the ones everybody has, in a systematic and logical way as much as possible. Eventually I classified the structure of staircases into two categories of the escaping routes and then into four categories in total. They are:

(A) Staircases inside the building (A1) Not separated from the rooms of the floor
(A2) Separated from the rooms of the floor
(B) Staircases on the outside walls of the building (B1) To be used only in emergency cases
(B2) To be used regularly all the time

This kind of classification of the staicases may seem trivial, but very important. Classification is the process of defining concepts. The classification should be able to sort various staircases of different shapes and structures smoothly and properly. I tried to recall the images of a large number of high-rise office buildings, department stores, hotels, university buildings, apartment buildings, shopping center buildings, etc. in Kasumigaseki, Shinjuku, and many other areas and tried to categorize the features of their staircases. The system of classification must be able to accept any conventional staircase in one of the categories. Furthermore, the classification system should be able to state that the staircase design newly proposed in the present invention demands a new category in the classification framework.

In the sections of conventional means and their problems, I first describe various convnetional means for escaping and rescuing people from fire in its overviews and then put stress on the necessity of effectively using the staircases. This corresponds to the problem situation and its focus; the thought for the problem definition must be explained here logically. By stating the problem situation thoroughly, the significance of the problem and the possible merit obtainable as the result of a good solution will become more convincing.

Problems of the conventional means are further analyzed for each of the four categories of staircases. Problems of staircases as the escaping routes in case of fire are pointed out as follows: Category (A1) is defective becasue the fire can spread easily. The separated internal staircases of Category (A2) aim to prevent the fire from extending and to serve as escaping route, but in fact have the drawbacks of becoming useless once the fire or smoke comes in due to the chimney effects. From the view point of escaping route in case of fire, the staircases (B1) and (B2) built on the outside walls of the buildings are perfect.

Then, should we just adopt such external staircases? No, unfortunately. Staircases built on the outside walls of the building have their own problems concerning the safety in ordinary days. The emergency-only staircases (B1) have the risks of being left open either intently or unintently. The free-access external staircases (B2) are often used at apartment buildings, where every flat is managed and locked independently by the residents. Such scheme of safety management may not always be convenient for big buildings of varaious usage.

This process of analyzing and describing the problems of conventional means is close to the analysis process in TRIZ. In practice, I made this analysis work with full usage of a number of TRIZ methods in my mind. Thus, the actual way of my thinking while I drafted the sections of ‘Problems of the conventional means’ and ‘Tasks to be solved’ is explained in the next section with explicit reference to TRIZ concepts.

3. Deriving Contradictions by the Use of TRIZ

The analysis described in the previous section has clearly shown the following points: For the purpose of making the escaping routes in case of fire, the staircases should be built not inside the building (i.e. Category (A2)) but outside the building on the outer wall (i.e. Categories (B1) and (B2)). However, from the viewpoints of the safety in ordinary days and the convenience and confortability for everyday use, staircases inside the buildings are much superior to those outside; thus the staircases outside the buildings may be adopted only for buildings of limited types of usage.

This statement corresponds exactly to the definition of a ‘Technical Contradiction’ in the TRIZ theory. We now consider a building as a system and are dealing with a staircase as its subsystem. In the staircase system, if we want to improve the system’s function as an escaping route (by locating the staircase on the outside wall), the system’s functions of convenience, confortability, and safety become intolerably worse. Namely, we are faced with a type of contradiction where “If we improve one aspect of the system, some other aspect gets intolerably worse.” This type of contradiction is called a ‘Technical Contradiction’ in TRIZ.

Being faced with such a contradiction, practical engineers often try trade-offs. Since no good compromise has been found in this case, however, most buildings of several stories adopt emergency-only external staircases while high-rise buildings adopt separated internal staircases without preparing for the emergency escaping. Hence breaking this contradiction is the task to be solved in this case study.

If you consider the above technical contradiction more carefully, you may naturally notice another view. It is the view distinguishing the time of emergency from much longer ordinary days. We want staircases to be convenient, sheltering from wind and rain, air-conditioned, and safely-guarded for the use of ordinary days. Emergency case of fire is the special period of time, when we want to ensure the staircase to be the route for escaping safely from fire. During this special time of fire nobody cares sheltering from rain and wind and safety from theft, etc.

Consideration of this kind of characteristics is always performed in the USIT method at the stage of ‘Analysis of space and time characteristics’. There continues a long period of ordinary time of everyday life, and suddenly the emergency of fire may arise. What and how to do during the ordinary days in preparation against unforeseeable emergency is the task of disaster preparation.

After thinking in this manner, the requirements for the design of staircase can be described as follows: “In order to be convenient, sheltering from wind and rain, air-conditioned, and safely-guarded against thefts in ordinary days, the staircase should be built inside the building, whereas the staircase should be built outside the building so as to keep it as the safe escaping route in case of fire.”

The above statement corresponds exactly to that of a ‘Physical Contradiction’ in TRIZ. The situation where “An aspect of a technical system is requested toward positive and toward negative at the same time” is called a ‘Physical Contradiction’ in TRIZ. In the present study, the staircase system is requested to be built inside the building to fulfill various requirements in ordinary days, whereas it is requested to be built outside the building for the requirements in case of fire. Namely, a staircase is under the contradictory requests that it should be built inside the building and outside the building at the same time.

TRIZ recommends us to solve problems by reformulating the problem into the Technical Contradictions and then further into the Physical Contradictions. Especially, TRIZ provides very clear and powerful principles for solving the Physical Contradictions. They are the ‘Separation Principles’. When we are faced with the contradiction where one aspect of the system is requested to be made in the positive and negative directions at the sametime, TRIZ asks us “Do the two opposite requests need to be fulfilled really simultaneously?” It urges to to think more closely: “Can’t you separate the two requests with respect to space? with respect to time? or with respect to some other condition?” In the present case, it is quite trivial that the two opposite requests (i.e. to be built inside/outside the building) refer to separated time periods, i.e. ordinary days and emergency time in case of fire.

The guideline in TRIZ to solve a Physical Contradiction with the separation principle is clear as follows: “In case the two requests are separated by the time, then during the time period when the request is positive we should fulfil the positive request, wheras during the time period when the request is negative we should just fulfil the negative request.” In the present case this means: “During the ordinary days the staircase should be built inside the building so as to be convenient, protecting from rain and wind, and air-conditioned, whereas during the emergency time of fire the staircase shold be built outside the building so as to keep it as the escaping route.” We must think over the real meaning of this message and how we can realize it, as the next step.

In this step of TRIZ method, to realize the stated requirement, some physical principle (or chemical, biological, social principle) need to be introduced, says Salamatov. In our case, we have to introduce some physical principle to realize the puzzling requirement, i.e. “To build the staircase inside the building during ordinary days and outside the building in case of fire”.

In the present case, such a principle (or a clew to solve the puzzle) is easily found among common sense knowledge of ordinary people: “To equip big windows (i.e. openings) at every floor of the staircase and open them widely in case of fire, so as to achieve the effect similar to that of rebuilding the staircase outside the building.”

This clew has come from the common sense knowledge, but in fact is based on a physical principle of the chimney effects. The staircases inside the buildings have the demerits of quick extension of fire and smoke because of the chimney effects and of becoming unavailable as the escaping routes. The external staircases, on the other hand, have been designed for the intention of avoiding the chimney effects.

The chimney effects can be described in a more scientific way as follows: If there is a hollow cylinder stretched long in the vertical direction and if the bottom (or middle) part contain hotter air, then a strong airflow is induced in the cylinder from the bottom to the top. If an opening is made in the middle of the cylinder, the “chimney” is effectively cut into two halves, making the airflow localised and weak as a whole. Since we know well about this physical effect, the naive idea of making windows at the every floor of the staircase is understood to have some scientific basis and is expected to work.

As explained above, TRIZ supposes to refer, after formulating the (physical) contradiction, to some scientific and technical principles for finding a solution to the contradiction. However, the consideration with scientific and technical principles should be made not only in such a late stage of problem solving process. In fact, in the USIT method, i.e. a simplified TRIZ method, the physical mechanism of the problem is examined and the plausible root causes are searched at the early stage of the problem definition.

Thus, in the USIT approach, at the initial stage of considering the present problem, the essence of the problem is found to be “Staircases built inside the buildings behave like a chimney in case of fire and become unavailable as escaping routes”, and then its physical mechanism is considered. The (scientific/engineering) consideration about the chimney effects lead us to understand that the long hollow structure in the vertical direction causes the effects. “If it’s the case, we should just make windows as openings and divide the hollow cylinder into smaller ones.” — this idea will come out at an easy step.

4. Constructing Solutions and Implementing with Technology

We have now solved the contradictions and obtained a basic idea clearly. Hence at the next step, we should extend the core idea and make various technical considerations to construct a united and practically feasible solution. I carried out this stage of work by drafting the section “Means to solve the problems” of the ‘Description of an Invention’. I wrote the section with a number of minor revisions. The orders of the ideas coming out were not the same as their orders written in the final document, of course. However, the main process of thinking was nearly the same in order as the final document.

The main ideas of the solution are as follows, as extracted from the document:

(1) To fulfill the convenience in ordinary time, the staircase should basically be a kind of ‘Internal Staircase’.
(2) The staircase should be of a ‘Separated’ type of ‘Internal Staircase’, in order to prevent the extension of fire and to keep it as an escaping route.
(3) In case of fire and earthquake, the windows of the staircase are opened widely.
(4) The open windows of the staircase may be used as the entrance for fire-distinguishing and rescuing activities during the emergency.
(5) The windows of the staircase should be able to be opened in case of fire remotely at the control center of the building.

These ideas are written in a top-down style from the main principle of design to some details. First the new design of the staircase is specified as an ‘Internal Staircase’, and then of the ‘Separated’ type, similar to the (A2) type of the conventional design. At item (3), it is further specified that the windows of the staircase should be opened widely in case of fire. This specification is the essence of the solution in the present invention. The items of (1) and (2) describe the basic design of the staircase in the ordinary days, and form a unified solution together with the item (3).

The specification (4) makes the openings of the staircase serve as the entrance and action basis for the fire-distinguishing and rescuing activities, and claims the function as an additional merit. TRIZ recommends that, after the introduced of a new solution into a part of the system, one should examine other parts of the system to make full use of the merit of the new solution and further improve the supersystem. In case of fire, the newly-designed staircases are available not only to go down for escaping but also to stay there safely for some time even while the building is burning. The space of safe staircase should be used actively for fire distinguishing and rescuing people. The widely opened windows make it easier for the firemen and rescuing teams to perform their activities with keeping communication with the staff outside the building; it is a merit that the controlling staff of the fire-fighting troop can observe their teams’ activities and guide them.

The item (5) specifies how to control this facility of windows. In the design of technical systems, it is essential to describe how to control them. Here I wrote about the control system after imaging modern high-rise buildings. It also specifies the control scheme so that the people there can take their best ways after their judgement in the emergency.

In the process of drafting the present solution, the ‘Analysis of space and time characteristics’ method in USIT was very useful and illustrative for me. USIT recommends to analyse the characteristics of the system in accordance with the ‘time axis’ specifically taken for the system. Thus, various possible situations in case of fire are considered along the time axis: Ordinary days without fire; the first stage of a small fire (and getting out of the floor/building); the second stage of a fire beginning to burn in a floor (and emergency evacuation of the floor/building); next stage of fire burning in multiple stories (and emergency escaping from the building and rescuing people); more serious stage of fire when the smoke and fire enter into the staircase (and emergency escaping and rescuing people); and so on. Consideration about these stages of fire step by step was helpful to think of the problems and necessary solutions in different stages.

In the present study, the solutions described above were obtained through knowledge in the level of common sense. If one deals with different problems, one may certainly need much more knowledge in technical specialities. Even so, I feel there may be rather large areas where the essence of solutions can be found by non-specialists.

5. Concerning the Uncompleted Parts in the ‘Description of an Invention’

There are three main parts which I have not completed in the above ‘Description of an Invention’. The first part is ‘Examples of Application’. As a document for applying a patent in this case, we should just show basic drawings of design; it is not requested to actually build a high-rise building with the staircase of such a design. I suppose most readers can imagine a staircase of the present idea without showing the drawings. To implement the idea and further improve the design of the solution, it is of course desirable and necessary to get help of specialists in architecture and in fire fighting and to examine in practice.

The second uncompleted part is the description of ‘Effects’. The effects and performance of the new design must be tested by model experiments and confirmed in practice. It is also desirable to derive a designing guideline for achieving the effects as expected.

The last part uncompleted in the document is the statement of claims as patents. To fill this part, one should survey conventional techniques and previous patents thoroughly and write down what is claimed as new original ideas in the present request of a patent. It is usually advised to write in general terms, so as not to restrict the claims unnecessarily, and to make the claims cover as widely as possible. Since it is difficult to write this part well, it is usually recommended to write down the drafts and ask patent specialists to brush them up.

6. What To Be Done in Future To Establish the Solution as New Techniques

As written in the preface of this page, I have just formed and documented the present idea, and decided not to try to file a patent but to publicize it as widely as possible. It is desirable and necessary to do some model experiments for checking the performance, to design and implement in real high-rise buildings, and to make design guidelines if good performance is achieved; all these work will need commitments by specialists in the fields of architecture, fire fighting, etc.

I should appreciate it very much if readers of this article would examine the present idea and improve it further into good solutions for safe escaping from fire.

(D) Note: A brief Introduction to TRIZ and USIT (Aug. 24, 2000) [English translation by Nakagawa, Dec. 22, 2000 (posted on Feb. 28, 2001)]

TRIZ (as pronounced like “trees” in English) is the abbriviation of Russian “Theory of Inventive Problem Solving”, i.e. a methodology for technical innovation developed first in the former USSR. Mr. G. S. Altshuller obtained its first idea in 1946 and have developed the methodology through the fifty years of collaboration with his students/followers in the grass-root organizations. After the end of the Cold War, TRIZ has become known to the West by a number of TRIZ specialists who emigrated to USA and Europe. It has been accepted in the West with much excitement and surprise. TRIZ has been introduced into Japan since 1997.

By reviewing the system of science and technology in the bottom-up manner from technological practice, TRIZ has developed new system of laws, such as the laws of evolution of technical systems, the principles of invention, standard solutions for invention, etc. It recommends us to analyze any technical problem to formulate contradictions, and then to solve the contradictions without making any compromise. It gives us a new way of thinking for achieving break-through solutions. The excellent and huge knowledge-bases accumulated in the study of TRIZ have already been installed into software tools which can work smoothly on PCs.

TRIZ is a powerful methodology having a huge system of knowledge base and methods. So it takes rather a long time to penetrate into industrial engineers. Thus there has been a number of attempts to simpify the process of problem solving by fully adopting the essence of TRIZ. USIT (i.e. ‘Unified Structured Inventive Thinking’) is one of such simplified methodologies developed in USA. It recommends a simple yet powerful process of problem solving, composed of three stages, i.e. Problem definition, Problem analysis, and Concept generation.

In Japan, TRIZ has been introduced and promoted by Nikkei Mechanical Journal, Mitsubishi Research Institute, Sanno Institute of Management, Professor Hatamura’s group at the University of Tokyo, and the present author. There now appear a number of pioneering engineers in various Japanese industries. The present author has established a Web site for promoting TRIZ and USIT on a not-for-profit purpose and has been publicly posting a number of information.

For reference to information on TRIZ, please visit my Web site named ‘TRIZ Home Page in Japan’, which has English and Japanese pages in parallel. Introductory articles on TRIZ posted in the Web site would be useful for beginners in TRIZ. URL:

Top of this page A. Beginning & background B. Description of an Invention C. Actual Thinking Process D. Introduction to TRIZ & USIT