VENTILATION SMOKING ROOMS. The problem
A company in the province of Madrid, very sensitive to the problems of pollution in its premises due to cigarette smoke, decided to enable two smoking areas, a living room and a dining room. So that these areas were well ventilated he asked us for advice.
Data to take into account
Smoking room with dimensions of: 9.1 X 4.1 X 2.7 m., the distance to the ejection point is 12 m. Smokers' dining room with dimensions of: 3.5 X 5 X 2.7 m., the distance to the ejection point is 5 m.
Determination of needs
Since there is no specific standard that indicates the ventilation needs for this specific case, we take as a reference the Regulation of Thermal Installations in Buildings (RITE) that in its instruction ITE 0.2.2.2 called "Indoor air quality and ventilation", determines that the UNE-100 011 standard will be complied with which indicates that for bars and cafeterias an air renewal equivalent to 15 l / s of air per m2 will be applied or person, in ignorance of the number of people who will be in the room we will base our calculations on the surface of both premises.
Smoking room:
9.1 X 4.1 X 15 X 3,600 = 2,015 m3/hourDining room: 3.5 X 5 x 15 x 3,600 = 945 m3/hour
The Solution
The two rooms to be ventilated are located in different areas of the company, so the solutions will be independent. However, the principle will be the same, we will design each ventilation system with the aim of trying to "sweep", as far as possible, the entire surface of the room to be ventilated.
Smoking room:
In the false ceiling we will place a duct of 315 mm. in diameter that will cross longitudinally the room and from which 5 branches of 200mm. in diameter will come out at whose ends suction grids of the GCI-200 type will be connected. At the end of the general duct we will connect a ventilation box type CVB-240/180 1/3 HP expelling the air directly to the outside patio of the company. In anticipation that the entrance door to the room may be closed and to ensure good air circulation, an opening will be made in it that leaves a free area of 0.25 m2. In order not to be aware of the on and off of the installation, an SQA air quality probe will be installed, which will put the ventilation system into operation when a degree of indoor pollution is reached that will be regulated at the convenience of the client. Dining room:
Following the same criteria as in the previous case, we will pass through the false ceiling a duct of 250 mm. in diameter from which 3 branches of 200 mm will come out. at whose ends GCI-200 suction grids will be connected. In this case, the extractor that we will install will be a CVB/4-180/180 box of 1.5 hp. In this case, the grid to be installed at the entrance door must have a minimum area of 0.125 m2.
Here we will also control the installation using an SQA air quality probe. Chosen references
Large room:
• 1 CVB-240/180 1/3 hp ventilation box • 1 CAC-355 circular adaptation • 1 CRC-355/315 reduction • 5 VR-200 coupling • 5 GCI-200 circular grille • GSA-315 duct • 1 SQA air quality probe
Dining room:
• 1 CVB-240/180 1/3 hp ventilation box • 1 CAC-250 circular adaptation • 3 VR-200 coupling • 3 GCI-200 circular grille • GSA-250 duct • GSI-200 duct • 1 SQA air quality probe
EXTRACTION OF FUMES AND ODORS IN A HAMBURGER SHOP.
The problem
Ventilation for kitchens as a toilet area of a hamburger.
Data to take into account
Kitchen: The kitchen is equipped with two hoods under which an oven and a fryer are located. The property in its specification specifies that for these two elements ventilation flows of 1,000 and 900 cfm respectively (cfm: cubic feet/minute) are required.
Ducts: The duct for evacuation of fumes from the furnace, will be 8 m. in length and 4 cubits of 90o are foreseen. The duct for evacuation of fumes from the fryer, will be 6 m. long and 4 cubits of 90o are foreseen. Both ducts will lead to a general section of 7 m. with 2 cubits of 90o.
Toilets: The place has 1 toilet for men, 1 toilet for ladies, 1 toilet-dressing room for men and 1 toilet-dressing room for ladies where it is intended that each of them has an independent ventilation system although all finally converge in a single general duct.
Dimensions:• Ladies toilet: 8m.2 x 3m. height • Men's toilet: 7m.2 x 3m. height • Men's toilet-changing room: 10m.2 x 3 m. height • Ladies toilet-dressing room: 10m.2 x 3m. height
The entire premises have a false ceiling through which the ducts can run and the evacuation will be carried out through the roof of the building.
Determination of needs
Kitchen: As indicated above, the needs for the kitchen are determined by the property, so we limit ourselves to making the transformation to European measures and calculating the necessary ducts to evacuate the required flow.
Oven: 1,000 cfm x 1.7 = 1,700 m3/h. Fryer: 900 cfm x 1.7= 1.530 m3/h.Total: 3.230 m3/h.
Estimating a maximum transport speed of 9 m/s so that it is not very noisy, we will apply the following formula to determine the section of the ducts:
S = Q / ( v . 3600 )
From where:
• S = Duct section in m2 • Q = Flow rate in m3/h • V = Air velocity in the duct in m/s
Replacing the known values for the oven :
• Sh = 1700 / ( 9 x 3600 ) • Sh = 0.0525 m2
Which is equivalent to a duct of 260 mm. in diameter.
Performing the same operation for the fryer:
•Sf = 1530 / ( 9 x 3600 ) •Sf = 0.0472 m2
This is equivalent to a duct of 250 mm. in diameter. Since both ducts are attached to a general collector, to calculate the section of this duct, maintaining the same speed, we apply the same formula:
•St = 3230 / ( 9 x 3600 ) •St = 0.0997 m2
This is equivalent to a general duct of 355 mm. in diameter.
To determine the total pressure loss of this installation, we will take the two most unfavorable sections (oven and general duct) disregarding the fryer since the pressure to be overcome will be lower than that which will be determined by the oven:
Washbasins:
To determine the necessary ventilation for washbasins and public toilets, the RITE in its instruction ITE 02.2.2 refers us to the UNE 100.011-91 standard, which indicates a flow rate of 90 m3 / h ".. for each toilet or urinal..", in this instruction, no needs are determined for showers or other items such as sinks. For our part, we understand that these rooms can not be left without ventilation, so in each case we will add an amount of air to extract estimated depending on the volume of each toilet to avoid odors and humidity.
Kitchen:
As indicated above, each of the hoods will start a duct that in the case of the oven will be 260 mm. and in that of the 250 mm fryer, both will converge in a general duct of 355 mm. that will go up to the cover where the extractor element will be installed. Because it is a public use facility, the NBE-CPI 96 standard requires an extractor capable of evacuating fumes at 400o for 2 hours as a measure to protect the building in case of fire, also, and given that the installation would be carried out on the roof, a weather cover and a discharge visor with anti-bird grid were recommended to prevent the entry of foreign elements from the outside. Toilets and changing rooms: (fig.2)Each room would be equipped with an independent ventilation system and all would lead to a common duct through which the air would exit to the outside. Inside each toilet in the duct an anti-return gate would be placed to avoid the entry of air from the other toilets. This duct would branch out to place suction grids as directly as possible on each of the contaminating points.
To provide for a correct air renewal, it was proposed to make openings in the entrance doors to the toilets with the following sections:
• Ladies Toilet: 0.027" • Gentlemen Toilet: 0.033" • Gentlemen's Wardrobe: 0.033" • Ladies Wardrobe: 0.033"
Chosen References
Kitchen:
• 1 CVHT-12/12 900 rpm ventilation box with 3⁄4 hp engine • 1 CHTI-12 outdoor cover • 1 CVD-12 discharge visor
Toilets:
• 1 TD-500/160 T fan • 1 MCA-500/160 anti-return gate • 3 BOC-160 suction mouth • GSA-125, GSA-160, GSA-200 and GSA-315 flexbile tube • BA-50 adhesive band
Locker rooms:
• 1 TD-500/600 T Fan • 1 MCA-500160 Detour Gate • 4 BOC-160 Suction Mouth • GSA-125, GSA-160, GSA-200 and GSA-315 Flexbile Tube • BA-50 Adhesive Band
PUB VENTILATION
The problem
It is about ventilating a Pub that is being built in Granada in which on the days of maximum occupancy, 400 people are expected, which will generate a high degree of pollution and a rarefied environment.
Data to take into account
The premises have an area of 220 m2, a height of 3 and a false ceiling with a height of 0.35 m. It overlooks a street at one end and an inner courtyard at the opposite. The premises will have an air conditioning system through ducts, if the location of the same is unknown.
Determination of needs
In the RITE (Regulation of Thermal Installations in Buildings) and specifically in its instruction ITE 02.2.2 "Indoor air quality and ventilation" the flows necessary for the ventilation of different premises are specified, based on the UNE-100-011 standard. Since this type of enclosure is not strictly indicated, our calculation will be made with the criteria indicated for a cafeteria. For the ventilation of this type of premises, the UNE 100-011 91 standard indicates a flow rate of 15 l/s (54 m3/h) for each m2 of surface.
Consequently the required flow rate will be: Q = 220 x 54 = 11,880 m3/h
The Solution
In rooms with air conditioning through ducts, a part of the suction of the indoor unit can be connected to a duct that sucks air from the outside, to dilute the contaminants. However, in this case, given the significant flow to be moved, it is necessary to provide for an independent ventilation system for both impulsion and extraction to guarantee the adequate contribution of outside air. Consequently, it is proposed to install both systems with the following characteristics:
Chosen references
Impulsion:
• CVTT-18/18 750/375 rpm 4/0.6 KW
Extraction:
• CVTT-18/18 650/325 rpm 3/0.4 KW
Impulsion
A CVTT-18/18 750/375 rpm 4/0.6 KW type ventilation box will be installed together with a pre-filter to prevent dust from entering from the outside to the inside. This filter is intended for a maximum pressure loss of 15 mm a.c. It is also planned to install a silencer (maximum permissible pressure loss 10 mm.c.a.) in the suction mouth to avoid inconvenience to the neighbors. From the ventilation box will come a duct that should be as square as possible, but since the height of the false ceiling is only 35 cm, the possibility of using a duct of 1.2 x 0.35m should be contemplated. to allow the passage of the intended flow, (it would be better if it is possible that the duct was more proportionate). From this duct will come two branches of constant section (for example 0.6 x 0.35) in which no less than 6 grids will be installed in each one.
Extraction
A CVTT-18/18 650/325 rpm 3/0.4 KW ventilation box will also be installed for the extraction of fumes and their discharge to the street. A silencer will also be installed in this case on the discharge side to prevent noise from escaping into the street. The suction will be connected to a duct of 1.2 x 0.35 m. (better if it can be more proportionate), from which two branches will come out, of constant section, one of 0.4 x 0.35 m. for 4 grids and another 0.8 x 0.35 m. for 8 grids.
Other Considerations
Given the type of premises, two-speed ventilation boxes have been recommended, so that a low ventilation level can be maintained, adjusted to the number of people who are in the enclosure, and to the air conditioning, having to be put into operation at its maximum speed when the highest occupancy of the premises is reached (if a single speed is desired, it is enough to select the highest speed and power indicated). The situation of the air conditioning ducts is unknown, so the possible situation of the ventilation ducts must be adapted to them. The ventilation system can be operated by means of two air quality probes (SQA), connected at different levels of sensitivity and that govern a contactor to drive the devices to obtain the two speeds. These probes allow to "select" the degree of indoor air quality and activate the ventilation system automatically when the environment begins to be rarefied.
VENTILATION OF THE DINING ROOM OF A RESTAURANT.
The problem
This dining room was located on the second floor of a building in a busy street and, although it had windows, it was impossible to use them for ventilation since the noise from the outside was very annoying for customers.
Data to take into account
It is a rectangular enclosure of 15x6 m. with a height of 3 m. to a false ceiling with 2 access doors in which there is already a ventilation system through two ducts of 110 mm. in diameter from which 7 suction points have been removed distributed throughout the premises although the evacuated flow is clearly insufficient.
Determination of needs
To determine the flow necessary for proper ventilation, we rely on the Regulation of Thermal Installations in Buildings that in its instruction ITE 0.2.2.2 called "Indoor air quality and ventilation", determines that the standard will be met which indicates that for public dining rooms an air flow of 10 liters / second per person or 6 liters / second per m2 of surface is required. Since the number of people occupying the dining room is variable, we determined the necessary flow based on the square meters which gave us the following needs:
(15 * 6m) * 6 l/s = 540 l/s = 1.944 m3/h
The Solution
Given these flow needs, it was found that it was not possible to use the old installation since the speed of the air to be evacuated would have been so high that the noise produced would be unbearable. In this case, we were lucky that the false plaster ceiling was practically airtight and did not communicate with the other rooms of the premises, so we could use it as a "plenum" without the need to install ducts.
Chosen references
Extraction equipment:
• 1 Ventilation box CVB-240/180 1/6 hp 900 r.p.m. • 1 Protective hat CSC-240 • 1 Reduction CRC-355/315 • 6 Circular diffusers GCI-200 • 6 Couplings VR-200 EQUIPMENT
Impulse:
• 1 CVB-240/240 1/2 hp ventilation box at 1400 rpm.m. • 1 CSC-240 protective hat • 1 Dust filter • 2 Drive grilles
The ventilation was solved by installing a ventilation box in the patio of lights located at one end of the premises sucking directly from the false ceiling and placing 6 circular diffusers evenly distributed by the ceiling of the dining room. The discharge of air was carried out by a circular duct of 315 mm. through the courtyard of lights until it exceeds by 1 m. the roof of thebuilding and finished with a hat to protect it from the rain. To perform a correct ventilation, it was necessary to ensure the entry of a volume of clean air from the outside equal to that of the extracted air, for this a ventilation box of the same characteristics as the previous one located in the patio of lights was prescribed, driving air to the interior of the premises through a rectangular duct of 300 x 400 mm. located in the false ceiling along one of the walls with 2 drive grids with a total section of 0.25 m2 to achieve an air inlet speed of about 2.5 m / s and placed equidistant from the ends to achieve a good air sweep.
In order to avoid introducing impurities through the impulsion duct, the inlet of the ventilation box was protected with a dust filter. It was proposed optionally to control the ventilation automatically, the installation of an Air Quality Probe (SQA), which would drive the fans when the air was stale.
