Building Science and Services BLD62304
E-Portfolio Submission (Compilation of all semester 3 assignments)
Lau Sam 0339574 Lecturer: Ms. Sharon Teh Ai Ping
Building Science and Services BLD62304
Assignment 1 Lighting and VAC Design for Comfort
Lau Sam 0339574 Lecturer: Ms. Sharon Teh Ai Ping
Discomfort / Problem
Discomfort / Problem 1 Brightness from the window causes too much glare towards the working space, the ceiling light currently is using only one light bulb and is not able to balance out the overall brightness. Eye health is a major concern for prolong usage due to current global situation.
211 Lux on the right side of the room
V
Natural lighting during the day
13 Lux on the left side of the room
Discomfort / Problem 2 As mentioned from Discomfort 1, the current bulb alone is not bright enough to light up the entire room, especially at night, needing the aid of the standing lamp to provide additional brightness. Using the lux meter with just one bulb at night, the right side of the room is around 5 lux whereas the area directly under the light source is around 20 lux.
17 Lux under existing ceiling light, 2 Lux on the right side of the room
19 Lux under existing ceiling light with standing lamp turned on, 39 Lux on the right side of the room with standing lamp turned on Room lit with only the ceiling light
Discomfort / Problem 3 The standing lamp causes some obstruction, have to physically move the lamp away to access the cupboard on the right for items, but placement of the standing lamp is currently essential for comfortable lighting condition.
Space obstruction to light up the right side of the room
Discomfort / Problem 4 Current socket system not very ideal, not evenly spaced out between the walls for easier access of electric appliances like table lamp and laptop chargers. Amount is also not enough as there are at least 6 appliances that needs a socket for power, current solution is to use extension cables.
The use of extension cable, to power table and standing lamp, causing cable clutter
Discomfort / Problem 5 Current AC unit is only 1 horsepower. It is not powerful enough if the proposed changes towards the lighting is executed, the current unit will not be able to cool the room efficiently. Hence, an upgrade to a higher horsepower will be needed (calculation will be shown in the redesign section and explaining on why it needs to be upgraded).
Current horsepower of AC unit is insufficient to cool the entire room efficiently
Redesign
Redesign 1 Removed current recessed ceiling lighting system in exchange for four recessed led down light. The current lightbulb used is a single 15W LED bulb, which is then diffused through a matte textured glass panel, insufficient to light up the entire room. The new LED down lights are 4-inch 9W diffused LED lights placed in areas of the room where it can be evenly lit, which will provide sufficient lighting for each side depending on the situation, balancing out brightness imbalance in the room in the long run.
Cost of current lighting system Cost of fixture (without bulb): RM 11 Cost of standing lamp (without bulb): RM70 Cost of installation per fixture: RM 20 Bulb price for fixture and stand lamp: 2 x RM 10 = RM 20 Bulb lifespan: 2 years Total initial cost: RM70 + RM11 +RM20 = RM 101 Annual energy cost: 0.015 kW (W) x 2 (Fixtures) x 10 (hrs/day) x 0.4 (RM/kWH) x 365 (Days) = RM 43.80 Including lifespan (Times fixtures replaced in 12 years): Once ever 2 years, total 6 times including first installation for each system Total fixture, installation and bulb cost: RM11 + RM70 + (RM20 x 2 x 6) = RM321 Total operating cost: 12 (years) x RM43.80 = RM525.60 Total cost: RM525.60 + RM321 = RM846.60
Cost of proposed changes for new lighting system Cost of each fixture: RM69 Cost of installation per fixture: RM15 Total initial cost: (RM69 + RM15) x 4 = RM336 Annual energy cost: 0.009kW (9W) x 4 (Fixtures) x 10 (hrs/day) x 0.4 (RM/kWH) x 365 (days) = RM 52.60 Including lifespan (Times fixtures replaced in 12 years): Once every 5 Years, total 3 times including first installation. Total fixture & installation cost: RM336 x 3 (times) = RM1,008 Total operating cost: 12 (years) x RM52.60 = RM631.20 Total cost: RM631.20 + RM1,008 = RM1,639.20
Total cost for current lighting system in the span of the next 12 years is RM846.60, but it not ideal and may cause long term damage towards the eyes and may result in treatment which will cost more than a better lighting system. Proposed lighting system for the next 12 years will cost RM1,639.20, although it is double the price of the original lighting system, better lighting condition for the eyes is worth the investment in the long run.
Redesign 2 Redesign socket placement for the room, two under each table. Current socket placement is insufficient for daily use primarily where monitors, chargers, lamps and WI-FI routers are present. All are currently sharing a single socket through an extension cord. The use of extension cords over a long period of time with high wattage usage may result in damaging the cord itself and may result in unwanted in-house disaster. Extension cords are not quite cheap to replace too as they range from RM30 to RM100 depending on the quality and socket count, constant replacement is not ideal in the long run. With evenly distributed sockets and the removal of the standing lamp as mentioned in Redesign 1, the available sockets will be used for the essential electronics in the room.
Redesign 3 Removal of standing lamp. With the proposal of a new ceiling lighting system, there is no need for the standing lamp to be used in the room as they provide enough lighting to work in different time of the day. The reason of removal is also due to the lamp not being a direct source of lighting, the current setup seems to not provide enough lumens during night times, lux reading shows only around 30 lux, whereas the table lamp on the other table alone provides at most 300 lux. As I work and play in the same room on a daily basis for more than 10 hours, the proposed lighting system should provide more than enough lumens for working conditions.
Redesign 4 Changed current air conditioning unit horsepower to a higher horsepower, current unit is 1 horsepower. Reason for upgrade can be justified based on the calculations below.
Sizing for air conditioner Room area: 4.45 m x 2.95 m = 13.13 m^2 Btu/hr: 13.13 x 700 = 9,191 Btu/hr
Estimated occupants: 3 Btu/hr: 3 people x 500 = 1500 Btu/hr
Estimate heat from electrical equipment Monitor = 21 W, Laptop = 230 W, Lighting (ceiling light & table lamp) = 43W, Ceiling fan = 75W Total = 369W Btu/hr: 369W x 3.5 = 1,291.50 Btu/hr
Total Btu/hr: 9,191 Btu/hr + 1,500 Btu/hr + 1,291.5 Btu/hr = 11,982.5 Btu/hr
11,982.5 / 9800 = 1.22 hp
With the proposed changes to the room, calculated amount of horsepower needed for the room is more than 1 horsepower, hence rounding up to the nearest commercially available unit, it should be 1.5 horsepower to maintain a cool temperature when the room is under heavy use.
Bill of Quantities
CAD Drawings of Existing and Proposed Design
Perspective View of Proposed Design
Building Science and Services BLD62304
Assignment 2 Indoor Comfort Design and ‘Invention’
Lau Sam 0339574 Lecturer: Ms. Sharon Teh Ai Ping
2A Floor Plan & Wall Allocation
Measurements Wall Material: Concrete Wall Thickness: 150mm (all four walls) Wall Height: 3100mm Long Wall Length: 5600mm Short Wall Length: 2950mm Wooden Platform Dimension: 2750mm (L) x 190mm (H) x 2750mm (W) Door Frame + Door Dimension: 2100mm (H) x 940mm (W) Double Casement Window Dimension: 1180mm (H) x 1180mm (W) = 15ft2 Fixed Window Dimension: 1180mm (W) x 300mm (H) = 3.81ft2 Fixed Window Panel Area: 1140mm (L) x 240mm (H) = 273,600mm2 = 2.95ft2 Double Casement Aluminum Frame Area: [1180mm (L) x 1180mm (W)] – 2(1100mm x 480mm) = 336,440mm2 = 3.62ft2 Double Casement Window Panel Area: 480mm (W) x 1100mm (H) = 5.68ft2 Window Panel Thickness: 12.7mm Glass Thickness 6mm Cupboard Size: 2280mm (H) x 610mm (THK) x 1800mm (W)
R Value Website https://www.concreteconstruction.net/how-to/concrete-production-precast/what-affectsbasement-wall-r-value_o
Wall Temperature 7am Wall 1: 24.3°C / 75.74°F Wall 2: 24.3°C / 75.74°F Wall 3: 25°C / 77°F Wall 4: 24.6°C / 76.28°F
12pm Wall 1: 24.7°C / 76.46°F Wall 2: 24.7°C / 76.46°F Wall 3: 24.6°C / 76.28°F Wall 4: 24.6°C / 76.28°F
5pm Wall 1: 25.7°C / 78.26°F Wall 2: 25.7°C / 78.26°F Wall 3: 25.5°C / 77.9°F Wall 4: 25.6°C / 78.08°F
Wall Area Wall 1 Area: (5600mm x 3100mm) – (2750mm x 190mm) – (610mm x 2280mm) = 15,446,700mm2 = 166.27ft2 Wall 2 Area: (2750mm x 3100mm) – (1180mm x1180mm) – (1180mm x 300mm) – (2750mm x 190mm) = 6,256,100mm2 = 67.34ft2 Wall 3 Area: (5600mm x 3100mm) – (2750mm x 190mm) – (2100mm x 940mm) = 14,863,500mm2 = 160ft2 Wall 4 Area: 2750mm x 3100mm = 8,525,000mm2 = 91.76ft2
Calculation 7am (External Temperature: 81°F) Wall 1 Wall 1 q: [166.27ft2 x (81°F – 75.74°F)] / 1.23 = 711.04Btu/hr
Wall 2 Wall 2 q: [67.34ft2 x (81°F – 75.74°F)] / 1.23 = 287.98Btu/hr Double Casement Aluminum q: [3.62ft2 x (81°F – 75.74°F)] / 1.8 = 10.58Btu/hr Fixed Aluminum q: [3.81ft2 x (81°F – 75.74°F)] / 1.8 = 11.13Btu/hr Double Casement Window Panel q: 2{[5.68ft2 x (81°F – 75.74°F)] / 0.91} = 65.66Btu/hr Fixed Window Panel q: [2.95ft2 x (81°F – 75.74°F)] / 0.91 = 17.05Btu/hr
Wall 3 Wall 3 q: [160ft² x (77°F - 77°F)] / 1.23 = 0Btu/hr
Wall 4 Wall 4 q: [91.76ft2 x (76.28°F – 76.28°F)] / 1.23 = 0Btu/hr
12pm (External Temperature: 93°F) Wall 1 Wall 1 q: [166.27ft2 x (93°F – 76.46°F)] / 1.23 = 2,235.86Btu/hr
Wall 2 Wall 2 q: [67.34ft2 x (93°F – 76.46°F)] / 1.23 = 905.53Btu/hr Double Casement Aluminum q: [3.62ft2 x (93°F – 76.46°F)] / 1.8 = 33.26Btu/hr Fixed Aluminum q: [3.81ft2 x (93°F – 76.46°F)] / 1.8 = 35Btu/hr Double Casement Window Panel q: 2{[5.68ft2 x (93°F – 76.46°F)] / 0.91} = 206.48Btu/hr Fixed Window Panel q: [2.95ft2 x (93°F – 76.46°F)] / 0.91 = 53.62Btu/hr
Wall 3 Wall 3 q: [160ft² x (76.28°F - 76.28°F)] / 1.23 = 0Btu/hr
Wall 4 Wall 4 q: [91.76ft2 x (76.28°F – 76.28°F)] / 1.23 = 0Btu/hr
5pm (External Temperature: 93°F) Wall 1 Wall 1 q: [166.27ft2 x (93°F – 78.26°F)] / 1.23 = 1,992.54Btu/hr
Wall 2 Wall 2 q: [67.34ft2 x (93°F – 78.26°F)] / 1.23 = 807Btu/hr Double Casement Aluminum q: [3.62ft2 x (93°F – 78.26°F)] / 1.8 = 29.64Btu/hr Fixed Aluminum q: [3.81ft2 x (93°F – 78.26°F)] / 1.8 = 31.2Btu/hr Double Casement Window Panel q: 2{[5.68ft2 x (93°F – 78.26°F)] / 0.91} = 184Btu/hr Fixed Window Panel q: [2.95ft2 x (93°F – 78.26°F)] / 0.91 = 47.78Btu/hr
Wall 3 Wall 3 q: [160ft² x (77.9°F - 77.9°F)] / 1.23 = 0Btu/hr
Wall 4 Wall 4 q: [91.76ft2 x (78.08°F – 78.08°F)] / 1.23 = 0Btu/hr
Total Heat Transfer for Each Wall at Different Times 7am Wall 1: 711.04Btu/hr
Wall 2: 287.98Btu/hr + 10.58Btu/hr + 11.13Btu/hr + 65.66Btu/hr + 17.05Btu/hr = 391.42 Btu/hr
Wall 3: 0 Btu/hr
Wall 4: 0 Btu/hr
12pm Wall 1: 2,235.86Btu/hr
Wall 2: 905.53Btu/hr + 33.26Btu/hr + 35Btu/hr + 206.48Btu/hr + 53.62Btu/hr = 1,233.89 Btu/hr
Wall 3: 0 Btu/hr
Wall 4: 0 Btu/hr
5pm Wall 1: 1,992.54Btu/hr
Wall 2: 807Btu/hr + 29.64Btu/hr + 31.2Btu/hr + 184Btu/hr + 47.78Btu/hr = 1,099.62 Btu/hr
Wall 3: 0 Btu/hr
Wall 4: 0 Btu/hr
Conclusion Based on the calculations, wall 1 has a higher heat transfer rate in all 3 hours recorded. The area of the wall is relatively large and the wall’s other side is also facing the open air, which is more prone to heat change compared to the interior walls. Wall 2 has an opening for a fixed window and a double casement window, but the area is small compared to wall 1, hence the heat transfer rate of the wall alone is not as huge as wall 1, but the opening causes more heat to enter the room. Wall 3 and 4 both are interior walls, the room temperature measured from each location of the house shown in the floor plan (Figure 1) were the same, thus there is no heat transfer for the last two walls. In conclusion, wall 2 is the problematic wall.
Sketches and Pictures of Selected Room
Wall 1
Wall 3
Wall 2
Wall 4
Wall 1
Wall 3
Wall 2
Wall 4
2B Initial Ideas Ideas were sketched out briefly to get an idea on which direction that I would prefer. Did not want to go with something too simple, yet didn’t want to do something too complex. I ended up going with a shape that might look a bit more different than generic wall panels, but adequate to let myself try out different ideas as I went through the process.
Sketch 1
Sketch 2 (Chosen 5th Shape in Sketch)
Materials My direction of the design was to go for a light weight design. Considering the limitation of my tools at home, I strayed away from using any wood or heavy solid materials as they are rather pricey and my craftmanship with these materials is not perfect. Main materials that were used are listed below: 1. Cardboard 2. Impra Board 3. 25mm Thick Regular Sponge Foam
Reason for choosing cardboard as the shell of the panel is because I have some a lot of unused cardboard collected from a store that I used to work, before proceeding with this assignment, they were mostly unused for over a year, now being put into good use. For the insulating material, foam was used for the panel. Spray foam is an insulating material, but it requires a lot of experience to handle, having not touched spray foam before and not wanting to make a mess, I opted for a more basic sponge foam material which is more flexible to cut into any desired shapes, but not as effective as spray foam for reducing heat transfer.
Proof of cardboards available at home
As for aesthetics, only 2 items were used for the outer panels: 1. Satin Cloth 2. Teak Wood Colored Spray Paint
Miscellaneous items used: 1. 2. 3. 4. 5.
Velcro Masking Tape Super Glue Ice Cream Stick White Glue
Materials Used
Process
Cardboards were cut to desired shape and folded to desired shape, a total of 6 pieces were cut under the 13-inch constraint.
Sponge foam were then cut into the same shape as the cardboard, with the same 13-inch constraint, only this time they were cut in half to fit the design of the panel.
After the basic form is complete, the inner square-like shape is the cut out, this is for the panels to stack on each other. (Several aspects of this design were not taken into consideration, mistakes were realized during the process and was unable to backtrack.)
The main materials were then glued together creating a sandwiched layer. Additional cardboard cutouts were added later on to cover the panel making it more enclosed.
After the initial shape is done, of spray paint was added throughout the whole panel to create a uniform color.
Once the paint dried, velcro strips were then added to add a modular front panel, either for aesthetics or for function.
Satin cloth was sticked on to impra board cutouts with masking tape. The square-like cutout was a bit complex to cut, not very noticeable from afar (a mistake which I did not consider how to properly cut fabric). Satin cloth boards were then stick onto the panels.
Functional front boards were created for the board, making it more customizable to the liking of the user, while providing some function.
Another strip of impra board were added to the sides of the panels to allow it to be able to stick on walls as a standalone panel.
Installation The wall panel can be installed in two ways, either by stacking or by adhering velcro tape onto the wall. The wall panel is shaped in a merged trapezoid with cutouts on the top and the bottom for angular mounting method.
Various front boards are available for aesthetics and for function, users can have it customized according to their needs.
Panels are installed onto the wall as shown below:
Velcro strips are placed on the panel to mount on the wall
Mounted Panel
Stacked Panels Using Cutouts
Besides providing reduced heat transfer, the front of the board can be customized to function that suits the user’s needs. Example of functional front board on how it can be used:
Pencil Holder
Key Hook, Cable Hook
Pictures of Finished Product
Difficulties / Mistakes Encountered During the Process Multiple mishaps and difficulties were faced while in the making of the panels. 1. Failed to consider cutout angles I did not take into account that the angle of the cutout was not quite as big to fit other panels. It was in the late stage of the process until I realized the situation. 2. Failed consider that spray paint characteristics After spray painting on the materials to create a uniformed look, the paint on some areas started to peel when being abrased lightly, most notably the impra board. As of recording the presentation video, the paint were not holding very well, having peeled a lot. 3. Not the lightweight panel that was expected After making the panels, I did not expect the panels to be a little hefty than expected, I did not consider the how much weight was added as I sandwiched materials and glue together. 4. Making rash decision on the design I wanted to try out the design without thinking much, seeing what materials fit and what doesn’t as I make them. Would consider it a serious mistake as a lot of unexpected things can happen during the crafting process.
Panel Cost Item Super Glue Satin Fabric (1m x 1m) Spray Paint Impra Board Velcro Tape White Glue Sponge Foam
Unit Tube Piece Bottle Piece Roll Bottle Piece
Average cost per panel: RM 130.10 /3 = RM43.35
Quantity 2 2 1 2 4 1 2
Price (RM) 12.5 14 19.9 7.3 4 2.6 12 Sum (RM)
Total (RM) 25 28 19.9 14.6 16 2.6 24 130.1
Receipts
Design Value
Design Value
Total amount: RM 603 Average market acceptance price: RM603 / 15 = RM 40.20 Average cost per panel: RM 43.35
Design Value: RM 40.20 – RM 43.35 = -RM 3.15
Reflection The initial idea of the panel was to use something solid instead of using recycled materials, but considering the limited tools at hand, I decided to stick with recycled and light weight materials instead. In the process of making the panels, a lot of design mishaps happened, be it paint peeling off or the panels don’t seem to fit well in a certain angle. There are a lot of things that I wished I thought through before proceeding with the process, planning out in advance on what to do instead of deciding what to do next after a process. If solid materials and proper tools were used, I believe the outcome will be better than the current design. Based on the average market acceptance price, made me consider that it is probably not something everyone would buy in their household unless they have specific needs, which leads me to also reconsider how the panels can be redesign into a light weight panel instead of a thick one. The modularity of the panel might not also fit the lifestyle of everyone, since it could be a hassle to detach and reattach a new front board, so a redesign of the functional properties is also on the list. Mounting options is also an aspect to reconsider as not everyone would like to stick velcro strips on the wall just to use the panels, perhaps using hooks on a space saving pegboard design would be a better option. A smaller overall form factor may very well be what people are looking for, nothing too bulky or thick, something small enough to store and light enough to carry. Something the viewer during the presentation don’t see is that I used other small materials behind the scenes to hold certain panels because they tend to lean forward can create an uneven surface, and multiple things fell apart as I was filming the presentation. Overall, my panel design is not perfect, it is flawed in various aspects which I did not consider while making them, and a lesson to note to self to always plan out the process first before starting.
Building Science and Services BLD62304
Final Project Design of Building Services (IAD3 Integrated)
Lau Sam 0339574 Lecturer: Ms. Sharon Teh Ai Ping
A Site Selection & Qualitative Description of Incorporated Building Services
The selected area for this assignment is the first floor of the Godown Kuala Lumpur. The function of the selected floor is to provide a space for people who are interested in Tekat embroidery and have a workshop dedicated to beginners. Surrounding the main area are furniture consisting of tables, shelves and cupboard if the students require more space to work and store things temporarily. The workshop is limited a maximum of 10 people per session, including 2 tutors. There is also a small area allocated on the far corner for the administrator of the place to work. The building services that are installed are down lightings, different VAC for the spaces, water supply and drainage. The lighting in the workshop space is direct ceiling down light and are primarily placed around the workshop area to provide enough lumens when working with their art work. The same goes to the Administration Room as it requires enough lighting to do work. As the Administration Room is an enclosed space, the air conditioning unit will be place there to provide ventilation. Furthermore, the ceiling fans are placed around the workshop area to provide proper air ventilation. The water supply and drainage are directed towards the water closet and sinks in the toilet area. As the toilet area does not have any opening for windows, wall mounted ventilators are placed in each cubicle to provide adequate air flow for the toilet. For the surroundings of the area, lightings won’t be as focused as the workshop area, they are placed quite spaced out from one another to provide just enough lighting to do simple task, as people won’t be around those area for long. The floor plan and perspective views of the area will be shown below, together with annotation of the lightings, VAC, basin and water closet.
Perspective 1. Workshop Area & Toilet
Perspective 2. Administration Office
B Designing and Justification of Building Services Selection & Location
Building Services Design Justification Air Conditioner Sizing Calculation Room Area*: 2.8m x 4.7m = 13.16m2 *(Note: As the admin room consists of curved partition, measurements of the room will be of a rough estimate.) Btu/hr: 13.16 x 700 = 9,212 Btu/hr
Estimated occupants: 3 Btu/hr: 3 people x 500 = 1500 Btu/hr
Estimated heat from electrical equipment Monitor = 21W, Personal Computer = 650W, Lighting (ceiling) = 26W Total = 697W Btu/hr: 697W x 3.5 = 2,439.5 Btu/hr
Total Btu/hr: 9,212 Btu/hr + 1,500 Btu/hr + 2,439.5 Btu/hr = 13,151.5 Btu/hr
13,151.5 / 9800 = 1.34 hp
The calculated amount of horsepower needed for the room is more than 1 horsepower, hence rounding up to the nearest commercially available unit, it should be 1.5 horsepower to maintain a cool temperature when the room is under heavy use. Using a 1 horsepower will not be ideal as that would not be enough to cool the entire room during hot weathers.
Lighting Illuminance Level •
Lighting for Workshop: 650 lm/ft2
The workshop area requires a higher number of lumens than other forms of lighting, the space is mostly used for sewing, working on artworks, reading references and demonstration. Since there will be multiple task lighting placed around the area, one single fixture will not need a very high lumen value, hence 650 lumens per square feet is adequate to distribute light rays instead of using a single fixture with high lumen value, which is also not a very ideal choice.
•
Lighting for Toilet: 2000 lm/ft2
The two toilets near the workshop are enclosed with no windows, there will be no natural light to enter the area. As a single fixture will be placed in each toilet, a batten fixture with higher lumen value than the ones used in the workshop area will be required to illuminate the entire toilet. •
Lighting for Administration Office: 650 lm/ft2
The administration office is also considered under the same category as the workshop area, the user needs enough lumens to do their work and read documents in an enclosed space with no natural lighting. It should also be enough for the max occupants of 3 to comfortably see their surroundings while in the room. A total of 4 downlights will be placed in the room to distribute the light rays. •
Lighting for Surrounding Spaces and Stairs: 450 lm/ft2
The lumen value for these spaces does not need to be as the same as the other 2 spaces, hence lights required for these spaces do not require too many as they are going to be lightly used and the users will not be in that particular area for a prolonged period of time. Hence only a few downlights enough to illuminate the area will be placed, distance will be more spaced out compared to the workshop area.
Qualitative and quantitative justification (energy use, safety) to be included The workshop electrical building services will be used on a 6 days per week basis with each day on an estimated use of eight to nine hours per day. Each session of the workshop lasts for 3 hours and have an hour break which in theory that the electrical building services will not be in use during that hour until the next session which will go on for another 3 hours. For the admin office, an estimated time of 9 hours, 6 days per week of use will be considered, as the admin will be in the office the whole day with an hour of lunch break in between which the building services will not be in use. Lighting used in for the stairs at the end of the building for the first floor will just be 3 downlights with the same usage hours as the administration office. The ventilation fans in both of the toilets will be turned on 24/7, to provide proper air flow and prevent unbearable odours overtime.
Table 1. Monthly Energy Use and Bill
Based on the table above, the total bill for this floor alone a month is RM400.
C Water Supply Network & Drainage of Bathroom
D Integrated Building Services in Drawings