Director, Architectural Acoustics Group
After a full day in the office followed by 5 hours of travel, I’m ready for a good night’s sleep. I check in to a sleek new hotel, grab my bag, and head for the elevator, where I am greeted by a 8-foot tall banner with 12” lettering: QUIET PLEASE. It goes on. In all caps, although I’ll spare you that here: “For the comfort and enjoyment of all guests please keep voice, television, and door closure volumes to a minimum.” My heart sinks. They might have well announced, “We have noise problems in this hotel – good luck getting the sleep you need!” Warnings of “door closure volumes” have me envisioning an evening of restless disruption from doors slamming in the corridor all night long.
The hotel industry – all $493 Billion of it – has a noise problem. According to data collected on statista.com, “noise from other guests” is the number one complaint of hotel guests. Some hotels have strong design standards for sound isolation and other acoustical criteria; others do not. And even for brands where such standards exist, I know from firsthand experience that such performance standards do not always translate into an acoustically robust hotel building. It’s impossible for me to say where the breakdown occurs in every case, but I expect it is due to a combination of a lack of understanding on the part of building designers – not everyone knows what to make of STC, OITC, NC, and Ldn requirements, much less how to implement them – and a lack of enforcement of these standards, perhaps in the face of budgetary pressure or other project realities.
Thankfully, the story is not always so dour. At Acentech, we’ve had the great fortune of contributing to many highly successful designs of hotels and resorts, from quaint boutiques to luxury resorts, in new construction, adaptive reuse, and renovation. It can be done! A good night’s sleep in a hotel is not just a dream. And it doesn’t take 8-foot tall warning signs to accomplish, either.
The process to acoustical design success usually starts with consideration of the site. Is the building to be located in a noisy urban environment? Or alongside a highway or train line? When environmental noise is a potential concern, we typically start our work with a noise survey of the site, collecting data over several days so that we understand the potential noise impacts. This information allows us to set a design criterion for the sound isolation performance of windows and other building façade elements. The entire façade assembly must be considered in composite when assessing exterior noise. This is particularly critical for hotels using packaged terminal air conditioners (PTACs) or other through-wall ventilation systems, which can create a significant weakness in the sound isolation performance of the building façade.
Once exterior noise is addressed, sound isolation concerns come inside. Hotels and resorts with substantial amenity spaces, conference facilities, ballrooms, or retail need robust sound isolation from such “high activity” spaces to guestrooms. Often this requires a sound barrier ceiling design – a heavy ceiling, often suspended resiliently, that serves to block the sound of the wedding party dancing to The Twist from the sleeping traveler above who never liked Chubby Checker anyway. Once the sound barrier ceiling is on the drawings, the work of coordination begins – HVAC, sprinklers, lights, and sometimes a decorative finish ceiling (often with a sound-absorbing finish to control reverberation and the build-up of noise) all must coexist up in the ceiling space without compromising the effectiveness of the sound barrier.
Between guestrooms, the wall and floor/ceiling designs are critical. There are three basic tools that designers use to block sound: mass (does the wall have enough layers of gypsum board?), separation (can we afford a double wall, or failing that, resilient elements that de-couple one side of the wall from the other?), and insulation in between separated mass layers. Careful about using those resilient elements – anything that needs to get anchored to studs (headboard, TV, etc.) has the potential to short-circuit the effectiveness of such elements unless an appropriate detail is developed and followed during installation. The same three principles of sound isolation apply not just to walls but to floor/ceiling assemblies as well; and, an added consideration – footfall noise – is also important in floor/ceiling design, particularly now that guestrooms are increasingly moving away from carpeted floors. Hard floor finishes work best when installed on top of a resilient underlayment, to cushion the blow.
About those TVs – our favorite solution is to put them on credenzas or in floor-supported cabinetry. A wall-mounted TV is an option, but the details to get it right are fussier.
It’s not just the sounds from guestrooms that need consideration, either – ice machines, elevators, laundry facilities – there are many functions of a hotel that require a good sound isolation strategy.
And what about the doors? The worst offenders are communicating doors that directly connect guestrooms to one another. To work well, those doors must be heavy, very well sealed, and work well as a complete assembly (along with the frame, hardware, etc.) – a specialty acoustically rated door assembly is often appropriate. At the entry doors, a deep undercut – as handy as it may be for return air transfer – is an invitation to listen to noise in the corridor all night long. Full perimeter gaskets around a tight-fitting door are much preferred – although it is worth acknowledging that maintenance will be required to maintain the performance of the door seals over the life of these oft-used doors.
Finally, there’s the noise of the mechanical systems. We look for a Goldilocks solution here – not too loud, but not too quiet, either. No one wants to listen to a noisy machine grinding away in or above their room. By the same token, if the systems are quiet enough to hear a pin drop, you can be sure you’ll be able to hear your neighbor’s TV, too.
After all is said and done, a good design can indeed lead to a good night’s sleep. Best to give these issues consideration during design though, so that we needn’t resort to 8-foot tall QUIET PLEASE warning signs in our hotel lobbies. Sweet dreams, everybody.