Test Certificate of Bbc

ETMS ACOUSTICAL CONSLATANT 3-3-2015

Test report

Clint:

British Broadcasting Corporation In cairo

Test date:

28 – 5-2014

Location:

160 nile st. agouza – cairo – Egypt

Test method It is based on

ASTM E4I3-2004" Classification for Rating Sound insulation"

Project discretion

This studios based in Cairo Egypt and unique place in Cairo nile view It is complex of sound and shooting studio and outside noise was normally 75 db and when the rash hour it measurers 88 db and it is very high noise

And that use technique of wall damping construction for sound isolation

and it is a flat in the 3 floor and the flat at self have huge panoramic glass window for wonderfull view of the nile and the background noise is very huge and it is consist of

1-traffic noise

2-loudspeaker of the call of prayer

3- some festival on the Nile small ship

4- internal noise of the place ( can manage it )

1 E N G I N E E R I N G T O W E R K O R N I S H E L N I L E – E L M A A D I C A I R O 0


Test object

1- Measure outside studio background noise 2- Measure inside studio background noise 3- Compare the measurements with the standard

Description of test

Instruments: sound level meter paa3 S/N 00380650

ACOUSTICAL calibrator B&K S/N 1897713

PAA3 SOFTWARE

Mac book pro laptop

Test procedures

Closing all the doors and start test with

SPL meter

EQ OF room

RT 60

Space and time average

- Average 6 meter from entrance door - Average 300 sec time

1 E N G I N E E R I N G T O W E R K O R N I S H E L N I L E – E L M A A D I C A I R O Page 10


Test result

Test result are appended with summary provide as following

The status of audio booth – edit1-edit2-shooting studio1 – shooting studio 2

According to case study of all that rooms the thickness of isolated material enough to reach to the requirement

The measurement of wall :

Description Db from inside room Db out of roomAudio booth 32.00 85Edit1 34.6 85Edit 2 31.6 85

Audio booth



Edit 1

Edit 2

The measurement of door:

Description Db from inside room Db out of roomDoor 34db 61 db



Out of the room

Real time analyzer inside the studio with recommended NC:



The reverberation of the all rooms

1- Audio booth

2- Edit 1

3- Edit 2

1.1 Sound Requirements

Sound requirements are divided into the following different criteria:



1.1.1 Airborne Sound Insulation

The following minimum airborne sound insulation between different spaces, R´w (dB)1) are required:

From other space to the “Large” and “Medium” space , covered wall: 44 dB 2)

From other space to the “Large” and “Medium” Conference room, all glass wall: Optimal 40 dB, minimum 37 dB.

From other space to the “small” and “XSmall” room. Optimal 40 dB, minimum 35 dB 3).

From Corridor4) to rooms: 35 dB 3)

It is recommended that the door should be classified (laboratory value) with minimum Rw 35 dB.

1) Or the equivalent values according to Sound Transmission Class (STC) from ASTM

2) The subjective perception of R´w 44 dB is that normal conversation cannot be heard, conversation with raised voices and shriek can be heard.

3) The subjective perception of R´w 35 dB is that normal conversation can be heard and conversation with raised voices can be perceived.

4) Applies normally for the wall with door.

Requirements in detail:Airborne sound insulation is expressed in terms of a weighted field sound reduction index R’w [dB] 1) according to international standards, e.g. ISO 717-1. Measurements shall be done according to international standards, e.g. ISO 140-4.

1) Field value (R’w) = the actual sound insulation that is measured in the finished building, e.g. between two rooms.Laboratory value (Dn,c,w and Rw) = The sound insulation that is measured in laboratories with the special conditions applying just there. When a supplier describes his product’s sound insulation ability it is often a laboratory value.

1.1.2 Impact sound insulation

Impact sound insulation is needed to prevent disturbance due to e.g. people's footsteps and scraping of chairs. The impact sound insulation capacity of the construction is measured as the level of impact sound in adjoining spaces.



Maximum impact sound level in the meeting room: from any other space: 65 dB from corridor: 60 dB

Requirements in detail:Impact sound level is expressed as the weighted impact sound level L’n,w [dB] according to international standards, e.g. ISO 717-2. Measurements shall be done according to e.g. ISO 140-7.

1.1.3 Room Acoustic

Room acoustical measures are needed to achieve optimum audibility, to increase the sound propagation losses, to improve work environment and to reduce noise level.

There are several terms for description of room acoustical qualities. The reverberation time is the most common method and is also the term which is easiest to understand subjectively.

The reverberation time in the meeting room should be 0,3 to 0,5 seconds1)

1) Reverberation time can be hard to estimate without thorough measurements. Opposing parallel surfaces may cause flutter echoes stemming from the sound bouncing back from the parallel surfaces over and over again. A very practical test to check for this is to stand in various positions in the room and clap your hands loudly once in every position. If the clap sound is crisp, clear and distinguishable then the acoustics of the room are good enough for video conferencing. On the other hand, if you hear diffusions as though more people are clapping their hands at the same time, there is flutter echo present and this will affect the sonic quality of the room. This will call for adding absorbers in the room, see below

Another way of stating requirement on room acoustics is to state the least area of absorbers, as the proportion of the ceiling surface, and the absorption class of the absorber. Sound absorbers are classified in accordance with ISO 11654.

The suspended ceiling should consist of absorber tiles according to Absorber Class A (ISO 11654)1) and cover as much as possible of the ceiling.

Installing absorbers also on walls (approx 10% of wall area) will generally improve the acoustics.

1) Or corresponding quality of NRC – Noise Reduction Coefficient, or SAA - Sound Absorption Average from ASTM C423.



In larger rooms, auditoriums, and larger rooms for training/education et cetera a more thorough planning is advised. Absorbers should be worked out and placed regarding room size, room shape and form of work. Some basic principles:

In long rooms (>9m) the rear wall should be fitted with absorbers or sound diffusing material. Alternatively the rear wall is inclined. (Bookshelves, cabinets, panel work or other equipment has a favorable effect).

In rooms with large clear floor space or varying furnishing, there will be a risk of flutter echo between floor and ceiling. In order to avoid flutter echo in such cases, the ceiling could be constructed with a combination of reflecting and absorbing material.

In order to increase the perceptibility of voice and facilitate for speakers in large rooms, the ceiling can contribute with useful sound reflection. Also in these cases the ceiling could be constructed with a combination of reflecting and absorbing material or with absorbers with lower sound absorption at medium and high frequencies.

1.1.4 Noise from services and appliances

The term noise from services and appliances refers to the maximum total sound level from all services and appliances in normally furnished spaces. The requirements relate to the aggregate sound level from all services and appliances, which generate noise of long duration. Examples of these are HVAC systems (Heating, Ventilation and Air Conditioning systems), lifts when in operation, et cetera.

Max allowed: 40 dB(A) Optimal: < 35 dB(A)



Requirements in detail and more reading:The given requirements for noise of long duration relate to the mean sound level, i.e. the equivalent sound level. The total maximum sound level due to noise of short duration that can be accepted is 5 dB(A) higher. Examples of this are running of water, starting and stopping of lifts. The requirements apply for the maximum sound level (LAmax) which is the highest recorded instantaneous sound level measured with time weighting S (slow). LA is the A-weighted sound level pressure designated dB(A) which is read on a sound level meter that complies with the requirements in international standard, IEC Publication No 651 or equivalent.

Sound pressure level at low frequencies shall be limited. To fulfill this requirement the C-weighted sound level pressure designated dB(C) shall not exceed 55 within the Occupation Zone.

1.1.5 Traffic Noise

Traffic noise is noise from road, rail and air traffic.

The sound level inside the meeting room due to traffic noise is expressed in terms of the equivalent sound level per 24 hours (mean value), designated dB(A), and the maximum instantaneous sound level (of short duration) in dB(A), with time weighting F (Fast).

The highest equivalent sound level / instantaneous sound level due to all normal traffic outside the building apply indoors in normally furnished spaces with windows closed. I.e “mean value” dB(A) / “short duration” dB(A):

Max allowed: 40 dB(A) / 55 dB(A) Optimal: < 35 dB(A) / 50 dB(A)

Conclusion :

Enoshmink had finished the work in the studios of BBC on 28/2/2015 and the work was checked by enoshmink and we have the final result that achieve ur technical requirments in the rooms

Dr. ibrahim elnoshokaty

2015

1 E N G I N E E R I N G T O W E R K O R N I S H E L N I L E – E L M A A D I C A I R O

Test Certificate of Bbc

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