When it comes to building automation systems, not all uses of the term “open system” are equal. When talking about open systems, definitions typically fall into three categories: open distribution, open protocols, and open service. This blog explores open distribution.

Definition
What does “open distribution” mean? Typically, it refers to the ability to purchase a single manufacturer’s product from multiple sources and have those products installed into a building. This is a different procurement model than purchasing products and solutions from an established manufacturer with controlled distribution. Many manufacturers of building automation have a blended approach to distribution that includes some aspects of both fully open and more controlled, often depending on the product line provided.

Some who position open systems focus heavily on the open distribution aspect of their product, minimizing other important aspects that should be considered. [For more context about open systems, read the blog Five Tips to Navigating the Complexity of Open System Building Controls]

Appeal
So, why do many find open distribution appealing? Common reasons include:

• Perceived Lower Cost. Building owners or design engineers want to be protected from perceived high costs of buying from a single source.
• Service Flexibility. Building owners want the flexibility to choose a service provider or be self-servicing, depending on staff and internal skillsets.
• Easy to Specify. Specifying a system that will solicit multiple bids is typically very easy when many contractors are available in a market (i.e. “The system shall be ABC product from XYZ manufacturer”). However, just because it’s easy doesn’t mean it will achieve the desired outcomes. Other system design aspects should be considered.

Considerations
There are some factors regarding an open distribution model that need to be considered when trying to achieve your goals.

• Quality Concerns. The more open a distribution model becomes, the more difficult it can be for a manufacturer to ensure a quality installation. Not all installing contractors have the same expertise and could change their product lines often, causing servicing challenges. Ensuring partnerships with reputable installers with long histories of quality installations and product representation longevity can help deliver a better outcome. Make sure the manufacturer will stand behind the installation, regardless of who is installing the system.
• Serviceability Challenges. System programming is often hard to service, especially in solutions that are based primarily on custom programming. Sometimes accessing the programming can be difficult because of  licensing complexities or  program locations within the system, which causes challenges down the road.
• Architecture Considerations. Some who focus on open distribution are primarily focusing on the system level building automation system. Often, the brand of unit level controllers may not be as openly available as first thought, leaving fewer service options.
• Proprietary Data. Other aspects of an open system, such as communications protocols, suffer when open distribution is the primary focus. Some systems don’t default to ASHRAE® Standard 135 BACnet protocol, which can cause expensive rework when integrating systems, migrating to new technologies or attempting to utilize building data for visualization or analytics.

Achieving An Open System
The desired outcome of the open distribution purchasing model can be achieved through good building automation system design. Some ways that design that can solicit multiple bids while mitigating some of the challenges many have experienced include:

• Choose the Right Partner. Business comes down to partnerships. Building a relationship with a reputable installing and servicing company is important to long term success. Using a controls manufacturer as a partner helps ensure a quality installation of a system by a company that will stand behind their reputation.
• Ensure Serviceability. Specify system documentation is delivered during the project – including manufacturer-supplied application guides, description of system operation, details of programming and accurate design documentation. Ensure that most common service functions can be performed by web browser without the need for configuration tools. For self-servicing owners, make certain you own all programming software needed to work on the building automation system and unit controls.
• Open Data. Any building automation system on the market should be able to comply with an open BACnet specification. Guaranteeing that systems are designed around open, standard BACnet will ensure multiple bids during the construction phase and provide the data needed to be successful in the future.
• Professional Training. Ultimately, you should be able to operate and service your system to whatever degree you choose. Make sure professional training offerings are available to familiarize you and your staff with the skills needed.

By: Andrew Disher, on Trane.com

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