January 2016


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Hans KranzEMAIL INTERVIEWHans Kranz and Ken Sinclair

Dipl.-Ing. Hans R. Kranz VDI, Forst / Baden
(active) retirement
Former member of DIN Presidial Board
Former Board Member of VDI-TGA
Former Project Leader ISO 16484

Functions of the Building Automation and Control Standard

The application of the building automation and control system function list (BACS FL) - ISO 16484-3

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Editor's note; as the presenter at this year's ControlTrends Hall of Fame Award I wish to share my new found knowledge of the amazing Hans and his many contributions to the industry.

From last month's interview See you in Orlando at CTA this announcement of the acknowledgment of Hans' achievements.

Smyers:  The ControlTrends Hall of Fame Award is a unique opportunity to recognize the true pioneers of our HVAC Industry. Our previous inductees include Werner Buck, Jerry Frank, George Thomas, and Michael Newman.  This year, logistics dictated that we have no element of surprise for one of the deserving inductees, Hans R. Kranz, from Germany, who is one of the founders of BACnet.  Hans Kranz is a remarkable man whose relentless and collaborative efforts led to the global adoption of BACnet.

A quick overview of Hans' contributions can be found in the below link.

Hans Kranz’s Curriculum Vitae for the 2016 ControlTrends Hall of Fame event

SinclairWhat was the reason for developing the Part 3, Functions. of the Building Automation and Control Standard?

Kranz:  When the DDCs began to develop in the HVAC field, the control was set by individual products such as analog controllers in the tenders. The building automation system was (and is) specified by data points.  Since that time, the complexity of the functions of rooms and facilities of a building is extremely grown.  The market still is calculating with hardware and data points - regardless of whether the data point is from a toilet fan or a heating-cooling air-conditioning unit. This resulted in not delivering adequate prices. Particular problems have occurred when there are changes in a project. How can you determine the prices for more or less data points, if there is no change the DDC hardware because of free terminals? But there is a lot of work to engineering. Over the years quite strange control function texts appeared for the bidding process. They were to read, like a voodoo dance description. This method of BACS sales staff (the consultants 'help') ensures that a competitor cannot understand what shall be delivered accurately. This in turn led to misinterpretations and wrong calculations - the "most incorrect' win the contract. This led to dissatisfaction with all stakeholders.

Let me say this important statement: Only manufacturers and installers with competent employees can ensure - at adequate prices - optimum deployment of building automation and control, including investment protection along with the required serviceability and functionality. This is sufficiently underscored by the number of bankruptcies, mergers and incomplete building automation and control projects over the past decades. I was told that there are these problems not only in Europe.

SinclairHow can the standardized functions help to avoid those dissatisfactions?

Kranz:  Adequate pricing only is possible when invitations to tender are legally certain. In general, invitations to tender must support the unambiguous exchange of information to secure free and fair competition, avoid unnecessary risks of cost and take advantage of the potential for innovation.  So, generally recognized standards and standardized methods are required to specify today's complex technical building automation and control systems. The principle of internationally standardized building automation and control functions is the base for better tendering - especially in system integration projects. There it is important to describe, which vendor has to do which part of the engineering work.  The functions, from the sensor input to the dynamic display are described clearly in Part 3 of the ISO standard. A consultant has to plan, and then to count and to put the number into items of work. This describes, together with the plant schematic, the required plant functions and provides additionally for a clear method to calculate the engineering costs. The standard provides the BACS function list for the purpose to document and to count the functions. In the tender, a standard function describes engineering services only - the complete required engineering work for a certain function. No hardware. The hardware is specified as a separate item.

SinclairCan this describe all conceivable system functions?

Kranz:  No, but about 90%. And that is more than we expected when we started to develop the standard functions within the VDI (The Association of German Engineers). Our Japanese ISO colleagues also could not imagine how to describe e. g. the functionality of packaged dual air-cooled brine chiller with ice storage system unit, with winter, transition period, and summer mode. After learning the handling of the function list and with a control flow chart diagram, they did! You can see the result as example B2 in the standard. Special, non standard plant requirements have to be described by explaining text. By the way: the BACS-FL also supports the design of systems using the BACnet protocol (ISO 16484-5).

SinclairIs there any help to fill in the function list in real projects?

Kranz:  Yes. There are several computer aided tools. With a CAD program one can design the building services plants or the room equipment. Then by key stroke the function list will be filled. Two examples are Mervisoft TRIC and WSCAD BAControl. There are others, even web-based (GFR Webproject).
This way of planning also provides for computer based tendering and bidding as used in some countries.

[an error occurred while processing this directive]SinclairHow did you ensure that the function list can be used in public procurement?

Kranz:  For many years it has been used in Germany. Now also in Austria and soon in Switzerland.  There are standard contract procedures (VOB) from DIN. It requires the ISO standard functions to be used as a work item. The relevant tendering texts are given by the standard specification of the Joint Committee for Information Technology in the Construction Industry (GAEB). There are some other guidelines and recommendations forcing the use of the ISO functions. e.g. from the Working Group Mechanical and Electrical Engineering of State and Municipal Administrations, AMEV.

SinclairThat sounds very interesting. Is there more information in English for learning more about this great method?

Kranz:  Certainly. I have prepared an article, especially for my American colleagues. They can study here on this website by downloading PDF. You also should have the ISO standard 16484-3 with it beside. The title of the article is: Application Of the BACS-FL - ISO 16484-3.
SinclairMany thanks for the insightful answers.
Kranz:  Thank you for the very competent questions.


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