• Justin P. Reidling
    • Adrian L. Lu, PE
    • Katherine M. Moore
    • Jordan L. Roberts
    • Lauren von Blohn
    • Wilson Shao
    • Winter R. Saeedi
    • Jake M. Schpero
    • Hester Ng
    • Matthew D. Hsiung
    • Nathan N. Sistek
    • Skyler Carrico
    • Aidan Nelson
    • Kenny Chong


Charles M. Salter Associates provides consulting and design services for clients interested in emergency communications systems (ECS) for their facilities. These life-safety systems provide targeted messaging to people within a building or across a campus. Timely and event-specific messages are broadcast over multiple media channels and deliver critical information to targeted groups in real-time.

Salter's approach links our acousticians and technology designers, specializing in audiovisual systems, telecommunications, and fire alarms, into a cohesive group that addresses emergency communication challenges. Salter does not sell, manufacture, or install equipment and therefore has no alliance with any brand or company. Our clients can count on unbiased recommendations and system designs that hold their best interests in mind.

Salter emergency communications services include:
   Risk assessments
   Architectural review
   System design
   Post installation speech intelligibility testing
   Coordinating and finalizing acceptance with AHJ
   Plan-check ready construction documents

Mass Communications Systems

In-building mass notification provides fire alarm and emergency communications to building occupants, informing them with clear and intelligible information on what actions they should take to respond to an emergency using audio, visual, textual, and video messaging.

Wide-area mass notification provides clear voice messages over high-powered loudspeaker arrays and other outdoor loudspeakers to alert an entire campus.

Distributed recipient mass notification uses electronic and telephony media such as email, text messages, reverse 911 telephone messages, and even social media to alert people of emergency conditions whether they are on or off of the facility premises.

Speech Intelligibility

The key to good voice communications is intelligibility, which is a measure of speech comprehension. Many factors affect intelligibility, particularly room reverberation. Intelligibility is measurable, and for emergency communication systems in California and many other states, minimum intelligibility criteria are included in the building code requirements.

For over 35 years, Salter has been a leader in intelligibility analyses. Salter acousticians understand how architectural properties affect speech intelligibility. We factor in the absorption coefficients of the materials on the walls, ceilings, floors, and furnishings; we also evaluate room and ceiling shapes to assist in the design of sound reinforcement systems. Our design will include the coordination of architectural, mechanical, and electronic solutions to overcome complicated acoustical challenges. The Salter team can also coordinate with the owner and end-user to develop prerecorded emergency message content that will improve listener comprehension of the emergency message in high stress emergency conditions.

Emergency Communications Systems Examples

In-Building Mass Notification System: If a fire is detected in the fourth floor north mechanical room, a message would be broadcast to people on the third, fourth, and fifth floors to evacuate using the south stairwell. The people on the other floors would receive a message to shelter in place until further notification.

Wide-Area Mass Notification System: If a fuel truck fire in front of the chemistry lab is threatening the building, the emergency message broadcast in the chemistry lab would advise occupants to immediately evacuate, using the courtyard exits and to muster at the courtyard emergency blue-light telephone. A broadcast to occupants at nearby buildings would warn to shelter in place. An alert to the rest of the campus would advise road and pedestrian closures around the chemistry lab. An email and text message to staff, students, and parents would alert them about the event and advise them to stay away from campus until an all-clear message is posted on the campus website.