Memo re noise pollution in Pilkington Building teaching rooms

Measuring the pollution

Due to recurrent complaints from students and teachers about the noise from the ventilation system, as well on the basis of my own experience of problems teaching in rooms 107 and 111 in the Sir Alistair Pilkington Building, I asked the University’s Health and Safety representatives to carry out ambient sound level checks on these locations.

At 11.15 a.m. on Monday 13 November 2000, the levels measured were as follows (decibels on A scale):

Pilkington room 107: overall ambient level 50 dB

at 63 Hz (mid octave) 57 dB

at 125 Hz (mid octave) 57 dB

at 250 Hz (mid octave) 53 dB

at 500 Hz (mid octave) 46 dB

at 1 kHz (mid octave) 43 dB

at 2 kHz (mid octave) 40dB

at 4 kHz (mid octave) 35 dB

The levels in Pilkington 111 were on average 2 dB below the values for room 107.

Effects of the pollution

Decibel measurements in the A scale, used above, are designed for registering the intensity of weak sounds. Values of sounds measured in the fifties (dB) of the A scale need to be increased to indicate their real effects on human perception (using the B or, more suitably, C scale).

The constant low-pitched sound measured in the Pilkington Building (57 dB A scale in the 63 and 125 Hz octaves) is equivalent to a continuous low drone played at medium volume on hi-fi equipment. Exposure to such constant low-frequency noise directly affects endocrine production (adrenalin etc.) which can give rise to headache, nausea and (indirectly) to tinnitus. Several students have complained to me of such effects.

Students have also complained that they must raise their voices in both rooms 107 and 111 in order to make themselves heard by the rest of the class. I have excellent hearing, but, when standing at the front of the class, I cannot hear students speaking in a normal voice at more than three metres distance. It is tiring, confusing and unpleasant to be obliged by the high level of ambient sound to talk much louder than one would under normal circumstances in the same space in an acoustically salutary teaching situation. One colleague has even been obliged to request that the building’s technician to supply him with a microphone when teaching in the Pilkington Building.

One important point of music teaching is to train students to listen carefully to the sounds around them. With the ongoing ambient noise of the building’s ventilation system, students learn instead to work in an acoustic environment where they are obliged to dispel the most unavoidable noise from their conscious. This state of affairs is not conducive to the fostering of aural awareness: rather, it directly obstructs one of the music teacher’s key tasks. Indeed, my annual lecture to first-year students on the soundscape and its relation to musical creativity, held for the first time in Pilkington 111, had to be abandoned because most of the sounds students need to register in the process of analysing our sonic environment were totally inaudible due to their masking by the noise of the building’s ventilation.

Given the current level of ambient sound in rooms 107 and 111, students cannot seriously be expected to focus attention on musical detail. Bass parts are virtually impossible to hear. Even if the volume is cranked up in vain attempts to drown out the ambient noise, the ventilation system produces tones which interfere with the music’s own sonorities (especially in the bass), providing fundamentals extraneous to the music and distorting the music’s harmonic structure. In other words, we are prevented from hearing the music as it is: we end up analysing and discussing something else.

In short, the air conditioning system in the Pilkington Building is a source of acoustic pollution which constitutes a danger to the health of students and teachers using its rooms 107 and 111. It also makes a mockery out of music teaching.

Possible solutions

Unless radical measures are taken to reduce the level of ambient noise to that of a normal teaching space without air conditioning or ventilation fans, it will be necessary to move all music teaching from rooms in the Pilkington Building which contain such noisy equipment. There is, for example, no way in which I will be able to teach next semester’s module ‘Music and the Moving Image 2’ under the acoustic circumstances we have had to endure this semester.

I am no acoustic design specialist or architect, but it seems that the current ventilation system is both unacceptable and dangerous. Judging from conversations with a consultant in acoustic design at the Chalmers College of Technology at the University of Göteborg (Sweden), it seems likely that the University of Liverpool may need to take one or more of the following measures: [1] replace the current system with a much quieter one; [2] insert (more) materials between the main ventilation motor and the walls of the building to soak up low-pitched vibration which may be affecting the fabric of the building and be transmitted into the teaching spaces; [3] counteract each source of noise with complementary noise from additional sources (this would have to be individually tailored for each teaching space and may in any event result in aggravating the noise pollution in some parts of the room while improving it in others); [4] allow teachers to switch off the ventilation system for the duration of their teaching; [5] allow teachers to open windows before teaching, during eventual breaks in their teaching, as well as after their teaching.

Liverpool, 27 November 2000

Philip Tagg

(Reader in Music)