BeaconMedæs Medical Gas Design Guide Chapter 1 - Design Process
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Part of the Atlas Copco Group
Notes
Notes on Using the Guide: This pamphlet is presented as a service to systems designers working with piped medical gases in medical facilities. The design process used in this booklet is detailed in this chapter. This Guide is not in any way intended to be a substitute for a properly qualified engineer, and any pretence to being alone sufficient for the proper design of any medical gas system is explicitly disclaimed. It is BeaconMedæs’ intent that this book should only be used as one tool among many by properly qualified engineers who are in a position by training and experience to know it’s applications and limitations. You will find in using the Guide that there are innumerable decisions, judgement calls, and subtleties in the design of medical gases which cannot be incorporated in any book, but serve to dramatically emphasize the value of the engineer’s expertise.
Fourth Edition November 2018 Replaces earlier edition of March 2009
Comments on this booklet or on any aspect of medical gases are welcome and encouraged. Please send to
[email protected]
This Pamphlet in both print and electronic versions is Copyright 2018 BeaconMedæs. All Rights are Reserved, and no reproduction may be made of the whole or any part without permission in writing. Distribution of the Electronic version is permitted only where the whole is transmitted without alteration, including this notice.
Chapter 1 Design Process
Introduction
The Design Process
Welcome to the BeaconMedæs Design Guide for medical gas systems.
Overleaf is the design process around which the Guide has been constructed. As you proceed through the Guide, you will find the respective icons for each of the phases there as a reminder of the process.
This Guide has become for many engineers their standard reference for medical gas design. However, the copy on their shelf may actually be under any of several names and they may not recognize they are working with the same document. The Medical Gas Design Guide was first published in 1991 by Ohmeda Medical Engineering. The Guide was reissued under the Medæs name around 1998, and then again revised and reissued by Hill Rom in February 2001 with a second edition in May of 2002. In all those reissues of course the products inside changed, but the document also suffered other less desirable changes as well. Above all, the Guide lost some of it’s clarity of mission. Originally conceived as a “cookbook”, where even an inexperienced engineer could manage the basics of a medical gas layout, the Guide became more coarse and less clear. The cookbook concept became diluted, whole sections were dropped, and the book lost its’ coherent design flow. It’s primary value was reduced to having everything you need in one place - provided you already knew how to use it. Through chance the Guide returned into the hands of some of those who originally conceived and drafted the 1991 edition, and was rewritten ground up in 2006 to restore that original flavor. The book continues to receive updates quite often, and additional tools have become available to assist with the use of the Guide. Most prominently, this includes the pipe sizing calculator which can be found on the BeaconMedaes web site and is not integrated into the Guide as the primary sizing tool for this edition. The Guide is written around a specific design process model which we believe to be the most practical and tested way to ensure the completeness and integrity of the final design. That process is detailed in this chapter and repeated as one follows through the Guide. To continue the cook book metaphor, this is the recipe on which this particular cook book is written. Page 3
There are four major phases, which may proceed concurrently or in sequence: Discovery, Design, Engineering, and Specification. Each of these phases calls for different skills, and therefore are often divided among several individuals in a firm. Discovery, the first and most important stage, is where the client lays out their needs and wishes. During these discussions you need a clear understanding of what you need to know. The forms included in this section are for your use as a starting point for development of your own more detailed interview guide. We suggest these forms be filled out during interviews with those people on the client’s site who are most knowledgeable about the existing systems and the intent of the new construction. A common mistake made by engineers is ignoring or curtailing the Discovery phase and relying instead on simple compliance with standards. There are no standards in the world which can substitute for an understanding of your client.
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An important trend in the process is that the owner and the architect are now taking on many of the functions which engineers formerly dealt with, such as placing outlets. The Discovery process herein explicitly includes this information. Alongside the strictly medical gas segment of the Discovery section we have included two activities which are no longer typically engineering responsibilities, but which may have the greatest impact on the final work of the engineer. These are the detailing and specification of the “architectural products” and the “medical convenience products” (headwalls, ceiling pendants, lab benches, etc.) which contain medical gases but are typically selected by the medical professionals or the architect. The decision process for these products frequently has Rev E 11/2018
BeaconMedæs Medical Gas Design Guide little or nothing to do with the engineering of the systems as such. Nevertheless, the medical gases must connect to them and be sized to serve them, so it is essential that the engineer understand the client’s choices and is aware of the details of these products and their construction. In specific, the number and placement of outlets and the details of how they are connected to the piping will impact the final verification of the systems, and thus the specification. Policies vary on how the discovery process should close, but we advocate a final memorandum signed by the relevant parties which constitutes the agreed requirements for the project. While it is obvious that things may have to change as the project design and construction proceeds, such a document gives the engineer a degree of confidence that they have captured the intent of their client before they spend a lot of the client’s money on design and engineering. The forms included here may be most useful in solidifying agreement on the memorandum. The Design phase is all about roughing in the various “big” elements of the system. It is during this phase that issues such as wall space for valves, sight lines for alarms, floorspace for source equipment and other problems which would later derail the project are identified. This phase should be completed as quickly as possible in the design process to ensure conflicts can be resolved prior to design finalization and construction start. Engineering is the next stage in the process. This is when equipment and systems are sized, equipment selected and final locations determined. Newer tools are simplifying this part of the process and saving time.
Finally, with all the above in hand, the Specification can be completed. We need not repeat all that has been said about the importance of spec writing, but we have provided a detailed guide specification which may help. Specification should be the easiest portion of the process particularly if you have followed the Guide to that point. Specification should not be neglected, as it is second only to the Discovery phase in ultimately ensuring that the final result is what you and your client expect. There is one more phase not discussed here because it is not part of the design process as such. Done properly, your work product from this Guide is an integrated system. It is not and should not be thought of any longer as a collection of components. An engineer or owner who foolishly allows a contractor to re-engineer their work by submission of components which have no virtue other than being “cheaper” has failed utterly. We do not argue that substitutions should never be allowed, nor that value engineering cannot be a useful contribution to the design process. We do argue that without reference to the knowledge gained during the discovery process, the many original design assumptions, and the original calculations, acceptance of such submissions is simply destructive. Any submitted alternate should receive the same scrutiny that the specified components will have received through this process. Acceptance of the 11th hour submittal of claimed-to-be “just as good and cheaper” product is simply not professional engineering.
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Numerous interfaces with other designers must occur in this phase, such as interface with the electrical engineers for power and signal wiring for medical air or vacuum plant, alarms and manifolds. Information systems planners must be informed what medical gases requirements to include in their networking requirements and on the Building Management Systems. HVAC may be required to ensure ventilation and possibly air conditioning for air cooled equipment. Site preparation may be required for liquid oxygen systems or manifolds located outdoors. Even your landscaping architects may need to get involved to ‘dress up’ outdoor equipment.
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Chapter 1
BeaconMedæs Medical Gas Design Guide Detail 1.5 The Design Process Map
Project Start
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Discovery Client interviews Site Visits Designation of “Category” for all Occupancies
Architectural Product Details Agreed Requirements Document
Design Place Outlets
Place Zone Valves
Route Piping
(Where this is not already provided by the Architect)
Place Other Valves
Place Alarms
Rough Locate Sources
Engineering
Size Sources 10
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Select Source Equipment
Confirm Source Locations
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Interface Alarms with BAS / other Detail Sources and Complete Pipe Routing
Detail and size Intakes/Exhausts & vents
Size Piping
Detail Alarms
Detail Electrical requirements
Specification General Conditions
Quality Assurance
Specify Installation Technique
Products & Services
Extent of Work
Submittals
Schedule Sources
Coordination
Verification
Specify Outlets
Specify Electrical Responsibilities
Specify Verification Technique
Specify Sources
Specify Valves
Schedule Alarms
Specify Verifier Qualifications
Specify Alarms
Specify Interfacing Methodology
Installer Qualifications
Design Process
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BeaconMedæs Medical Gas Design Guide Graphical Table of Contents Chapter 3
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3.4-3.15
3.7
3.4
Chapter 4 4.5
4.7, Chapter 5,6,7,8,9 4.9
4.10
4.9
4.12, Chapter 10
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Chapter 11
Chapter 10
Chapter 5,6,7,8,9
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Chapter 5,6,7,8,9
Engineering
Chapter 5,6,7,8,9 Size Sources
Select Source Equipment
Confirm Source Locations
Chapter 5,6,7,8,9
Detail Sources and Complete Pipe Routing
Detail Alarms
Size Piping
Detail Electrical requirements Detail and size Intakes/Exhausts & vents
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Interface Alarms with BAS / other
Chap.11 Chap. 5,6, 7,8,9,10 Chap. 5,6, 7,8,9,10
Chapter 1
BeaconMedæs Medical Gas Design Guide
Chapter 12
12.23
12.5 12.8
12.25 12.9
Chapter 5,6,7,8,9 Chapter 5,6,7,8,9 Chapter 4 Chapter 10
12.25
10.18
12.7 12.24
Design Process
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Part of the Atlas Copco Group
Rock Hill, SC 29732 • Phone 1 888 4 MED GAS www.beaconmedaes.com
