Basic Documentation

pressurization. These are among the most basic
laboratory ventilation requirements.
Numerous safety bodies insist on an active
monitoring device mounted on every fume hood.
This device indicates directly to the hood user that
the hood is functioning at the moment. Ideally, these
devices are also networked into the Building
Automation System so that building operators and
safety officials receive the same information.
Room pressurization is a ventilation strategy that
helps keep lab air contaminants from spreading
through the building. Safety bodies are in similar
agreement about this basic need. The system must
be designed, commissioned and operated for
effective pressurization. Long term monitoring is the
final step to assure quality. The BAS logs and
delivers this information using sensors in the space
and in the ventilation system. In some cases, room
users need pressurization displayed at the doorway.
Figure 7 is an example of such a display device.
Figure 7. Pressure Monitor at Doorway Keeps
Lab Workers Informed.
The Labs21 Criteria awards a point (EQ 9.3) for a
comprehensive alarm system to notify workers in the
room of any hazards. In addition to the hood and
pressurization alarms, this might include room
airflow rates, doors left open, equipment failures and
measured contaminants in the air.
Monitoring OA Delivery
A state of the art lab ventilation system, based on
airflow sensing and closed-loop control, and fully
integrated into the Building Automation System
earns this LEED credit. (EQ 1 for Outdoor Air
Delivery Monitoring.) The BAS delivers current
values to building operators, room occupants or
safety professionals. It annunciates ventilation
alarms where and when they are needed. It logs
data day after day for long term evaluation.
The ventilation rates commonly chosen in
laboratories, and the practice of supplying 100%
outdoor air, make it more practical to earn this point
by measuring the airflow than by inferring it from
CO
2
concentrations.
Controllability of Systems
Green buildings let occupants adjust their indoor
environment (LEED credits EQ 6.1 and 6.2). In some
cases, an ordinary room thermostat does the job.
Other cases call for an interactive display, where
workers in the room set their preferences for
temperature, humidity, light levels, etc. and the
system feeds back information on current settings
and conditions.
Specific solutions vary with the use of the room.
Some spaces are subject to thorough wash-down
and only the most rugged devices may be mounted
on the walls. In such cases, a small panel outside
the door or web access serves the users well.
A flexible, open BAS gives designers the options for
occupant interfaces so they can create labs that
work.
Fume Hood Commissioning
In many projects, the construction team certifies
operation of the fume hoods based on airflow
measurements, like face velocity or exhaust duct
flow rate. Industrial hygiene experts stress the value
of directly measuring the ability of the hood to
contain contaminants. ASHRAE established the
standard containment test procedure.
18
AIHA
endorses the procedure in the Laboratory Ventilation
Standard. The Labs21 group awards a point (EQ
9.1) for measuring containment on each hood.
Similarly, the USGBC has judged full ASHRAE 110
testing worthy of an ID point.
18. ASHRAE, ASHRAE Guidelines, "Method of Testing
Performance of Laboratory Fume Hoods", ANSI/ASHRAE
110-1995 (June 1995).
Siemens Industry, Inc. Page 13 of 14
Document No. 1
49-488