The solution that was found optimal for reduction of noise in a ward (especially public wards separated by thin sheets) was soundproof curtains.

To block out or significantly dampen noise, the curtain will have to be mounted on both the ceiling and floor by the use of rails. The rails on the floor will have a provision to incorporate infection control to prevent cross contamination across patient sections.

Additionally, the curtain will have thermal insulation properties keeping the patients in a comfortable warm or cool environment.

The cross section of the sound proof curtain is shown below. It is made up of sound dampening foam sandwiched between sound insulating fabrics. 


JUSTIFICATION FOR OUR DESIGN

There are different acoustic curtains currently in the market. They include the following among others:

• The RYB blackout curtains – are curtains with felt fabric liner for sound absorbing. They also have 3 soundproof layers that are also thermal insulated. The felt liner is sandwiched in between the blackout fabric forming three sound proof layers.
• H.VERSAILTEX Linen Curtains – these curtains have heavy weight textured rich linen that help in minimizing noise levels. They are made up of 85% fabric.

Most of the current products in the market are made of polyester fiber. According to Bai et al. (2018), polyester fiber's soundproofing performance is dependent on the thickness of the curtain; that is, thicker and denser polyester fiber has a better absorbing coefficient than less dense fibers. Curtains made of polyester curtains need to be about 24mm thick for the sound absorption coefficient to be 0.9. compared to this type of curtain, our design, which uses polyurethane foam sandwiched in between polypropylene fiber, has an absorption coefficient of 0.8 at 10mm thickness. This means that it is lighter than the market's existing product for almost similar absorption coefficients. Unlike polyester, which highly pollutes the environment, polypropylene is more environmentally friendly as it is recyclable, does not release many toxins to the environment, and breaks down faster than other plastics (Peng et al., 2015).
Our design also makes use of recycled textiles, which curbs environmental pollution. Other curtains are mass loaded with vinyl, which is very heavy and difficult to move. This becomes unideal in the hospital ward setup as the acoustic curtains need to be easily movable around a bed station (Simon, 2020). Therefore, the design solution we have come up with becomes more suitable than the currently available products in the market since not only is it effective in filtering out both high and low sound frequencies, but it is also much lighter. It also has antimicrobial properties as it is embedded with silver ions, which are effective antibacterial, thus enhancing infection control in the hospital. Our design also has good thermal insulating properties, fire redundant, and has low moisture-vapor permeability, which keeps the patient in a cool environment. The employment of polyurethane foam improves the properties of our design, not present in other acoustic curtains.

References
Bai, P. et al. (2018) 'Investigation on Sound Absorbing Performance of the Polyester Fiber for Noise Reduction in Large-scale Equipment', in IOP Conference Series: Materials Science and Engineering. Institute of Physics Publishing, p. 12004. doi: 10.1088/1757-899X/398/1/012004.

Peng, L. et al. (2015) 'Mechanic and acoustic properties of the sound-absorbing material made from natural fiber and polyester', Advances in Materials Science and Engineering. Hindawi Publishing Corporation, 2015. doi: 10.1155/2015/274913.

Simon, E. (2020) Understanding Sound Proof Curtains & Sound Absorbing Curtains, Direct Fabrics. Available at: https://www.direct-fabrics.co.uk/blog/understanding-acoustic-curtains-absorption-sound-proofing-curtains/ (Accessed: 12 January 2021).