ASHRAE Journal - February 2020 - 54

FEATURE

IT systems, which is common practice, and is
IT-friendly. The new protocol shifts BACnet into the
application space of using well-known, accepted IP
application protocols and techniques, according to
Bernhard Isler, Member ASHRAE, and a former chair
of the standard committee for ASHRAE Standard 135.
The protocol will provide inherent means of protection for BACnet-based building automation systems,
even across public internet or in shared, private IP
networks.
"BACnet Secure Connect will provide cybersecurity
inherently, equal to what is currently achieved using
VPNs and such. No extra VPN equipment or software
and according setups will be needed anymore," he
said.
BACnet Secure Connect allows devices to protect themselves with built-in security mechanisms and should
eliminate risky behavior such as placing unprotected
devices directly on the internet.
Michael Osborne, P.Eng., Member ASHRAE, chair of
SSPC 135, said the biggest challenge engineers will face

Two Crucial Standards for
Addressing Commercial O&M
For HVAC inspection and maintenance
requirements:
Standard 180-2018 - Standard Practice for Inspection
and Maintenance of Commercial Building HVAC Systems
(ANSI Approved; ACCA Co-sponsored)
For conducting and reporting energy audits:
Standard 211-2018 - Standard for Commercial Building
Energy Audits (ANSI Approved/ACCA Co-sponsored)
ashrae.org/180and211

ASHRAE JOURNAL

ashrae.org

FEBRUARY 2020

with BACnet/SC on the building and community levels
is the need to plan for and manage building automation
systems security.
From the BAS-design side, Osborne said industry professionals will have to decide if the BAS needs security
for external access only, at the IP level or to the sensor level. From the maintenance side, they will have to
decide who will create, maintain and update the needed
certificates for the BAS.

The Development Process
When SSPC 135 started developing what would become
BACnet/SC, there was a long list of requirements, said
Osborne.
"At the core of these was maintaining the BACnet data
model and services while updating BACnet communications to the latest IP infrastructure requirements. The
committee spent significant time and effort looking at
different solutions and initially settled on an entirely
new 'IT Layer' below the existing BACnet Application
layer along with a mechanism similar to BACnet/PTP to
transport existing BACnet packets across this secure network," he said.
After that solution went out for advisory public review
in 2016, the committee reconsidered this solution due to
the resulting comments, he said.
"After much discussion a hub and spoke model at
the datalink layer was chosen as a simpler solution
that covered the mandated requirements. To increase
the likelihood of existing BACnet products supporting
BACnet/SC the committee also ensured the addendum did not force an existing product to move to a
newer BACnet Protocol Revision to support this datalink," said Osborne, adding the next hurdles were to
overcome the inherent weaknesses of this model and
over the next two years BACnet Secure Connect was
developed.
Osborne said the immediate need is adding interoperable configuration to BACnet/SC. He said a proposal is in
process.

Guiding the HVAC&R Industry
ASHRAE's continuous maintenance standards undergo
major updates every four years following lengthy revision cycles. These standards guide the HVAC&R industry
to achieve best practices in how buildings are designed,
built and operated.

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ASHRAE Journal - February 2020

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