Hydrogels versus sand bags.
See the difference !
Hydrogels bags require
less organization, less planning, less material, less physical energy, less time, less space and less assistance...
In short, hydrogels bags do more...
They are more efficient, more economical and overall better for the environment.
Simulation
100 bags to be deployed ! Can a single person deploy them in just a day ?
It is possible with hydrogels bags !
Suppose that it is necessary to protect a piece of land over a distance of (L) 10 metres or 32.3 feet. Safe water height (H) set at 30 cm (12”).
A simple wall where N = 3 layers proves sufficient in the situation at hand and will cover the safe height of H.
N x 3 L
= 3 layers x 3 bags/metre x 10 metres to be protected
= 90 bags round up to the nearest ten
N x 1 L
= 3 layers x 1 bag/foot x 32.3 feet to be protected
= 100 bags round up to the nearest ten
Use Comparaison
HYDROGELS BAGS
SAND BAGS
TOTAL ESTIMATED TIME TO PUT IN PLACE THE 100 BAGS BARRIER
FOR SINGLE PERSON
BETWEEN 6 AND 14 HOURS FOR 100 HYDROGELS BAGS
MORE THAN 20 HOURS FOR 100 SAND BAGS
MATERIAL AND SPACE REQUIRED
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The three boxes of hydrogels bags contain a total of 100 standard bags 40 cm x 60 cm (16" x 24") ready for deployment.
Each box measures about 45 cm x 65 cm x 30 cm (18" x 26" x 12") and can hold up to 40 bags in total. Boxes can be stored in a garage, shed or closet provided they are not exposed to sunlight and kept in a dry location.
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Cutter and scissors to open boxes and packages.
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Two containers similar in size to the standard size bag and capable of holding at least 30 litres (7 US gallons) of liquid.
Or simply a rectangular container capable of holding up to 60 litres or more.
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A garden hose or water source close at hand.
Roll out the garden hose as close as possible to the site to be protected and location in which the bags are to be expanded. This will minimize personnel movement.
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If required, a pair of waterproof gloves and another pair of gloves for bag handling.
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Optional: Two 20-litre (5-gallon) pails with handles or equivalent.
The pails will serve to transport the bags manually to the site to be protected.
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A roll of a minimum of 100 heavy duty, similarly sized bags about 40 cm x 60 cm (16" x 24"). The number of bags per roll will vary from one supplier to the next.
Bags of this size normally boast a capacity of 30 kg (66 lb) when filled. It is preferable to use a natural fibre such as jute. In addition to being biodegradable, jute bags are tougher than nylon, polyethylene or polypropylene and better suited for field use. The roll of bags can be stored in a garage, shed or closet provided it is not exposed to sunlight and kept in a dry location.
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100 heavy duty ties to close the bags. Natural fibre cord is preferable albeit not as handy as nylon or chicken wire.
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Manual fastener/twister, pliers or pruning shears depending on the type of ties used.
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A minimum 3000 kg (6600 lb) load of sand and space for unloading.
This space must be located as close as possible to the site to be protected to minimize personnel movement given the weight of the sand bags. The cost of a load of sand will vary based on quantity and distance to be transported. Depending on the region and time of year, allow for thawing and winter handling charges.
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One shovel
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One rake.
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One wheelbarrow or equivalent for manual transport of bag.
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One pair of gloves.
DEPLOYMENT OF BAGS
Suggestion: Proceed 10 bags at a time.
Minimal reference time for single individual
10 Hydrogel bags expanded per hour or more
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Open one vacuum packed bag of 10 hydrogels bags.
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Fill a container, place the bag in water and allow to expand. Then repeat the procedure with a second container. This stage requires little in the way of physical effort and preparation, and saves energy for the erection of a protective barrier.
Refer to the following diagram :
CONTAINER FILLING TIME
3 minutes
based on 30-liter container
and average garden hose flow of 10 L/minute
HYDROGEL BAG EXPANSION TIME
< or = 7 minutes
First 30-litre container
Second 30-liter container
53 MINUTES TO EXPAND
10 HYDROGEL BAGS OF 15 KG (33 LB) EACH
Note 1 : It is possible to reduce preparation time without requesting the assistance of another individual by increasing water flow, having more than one water source at hand or increasing container volume.
Example:
IN THE PRECEDING DIAGRAM, USE 90-LITRE CONTAINERS, THE VOLUME OF OUR STARTER KIT, AND EXPAND THREE BAGS AT A TIME PER CONTAINER. Filling time will increase from 3 to 9 minutes, but in 16 minutes you will have expanded three bags. INFLATE 100 BAGS WILL TAKE ABOUT 4 HOURS AND HALF.
DOUBLE THE FLOW RATE and the 3 bags will be expanded in 12 minutes. INFLATE 100 BAGS WILL TAKE ABOUT 3 HOURS AND HALF.
Note that the flow rate of a standard garden hose is generally greater than 10 L/minute.
Reference time for single individual 10 sand bags in
1 hour 40 minutes
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Open the roll of 100 bags. Take out one bag and one tie.
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Hold the bag open for the first few shovelsful of sand. When the bag begins to retain its shape, it may be possible to fill it directly with sand without having to hold it open. For an individual working alone, it is preferable to devise a bag support technique to avoid having to hold the bag open with one hand and direct shovelsful of sand into the bag with the other. Bag loaders are available on the market but are often expensive and require added investment in materials.
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Fill the bags with approximately the same amount of sand to ensure that they are similar in size.
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Close each bag tightly with the chosen tie to ensure that no sand escapes. The point of closure will remain the weakest point of each bag.
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Note that at this stage, it will be necessary to physically handle 3 tonnes of sand for the first time.
Refer to the following diagram :
SAND BAG FILLING TIME
9 minutes
(Time varies considerably from one individual to the next)
Preparation of a 30 kg sand bag requires about 30 shovelsful of sand per bag and reasonable loading efficiency
SAND BAG CLOSING AND TYING TIME
1 minutes
(Time varies considerably from one individual to the next)
Linear progression only
. . .
1 HOUR 40 MINUTES TO PREPARE TEN 30 KG (66 LB)
BAGS OF SAND
Note 2 : It is impossible for an individual working alone to reduce bag preparation time without asking for assistance.
Individuals are dependent on the rate at which they shovel the 3000 kg of sand and their dexterity in filling, closing and tying the bags. To increase the number of bags per hour, they must optimize each of the steps involved.
BUILDING A PROTECTIVE BARRIER
ALLOW ABOUT 20 MINUTES TO TRANSPORT
AND POSITION 10 WATER GEL BAGS
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Transport the expanded bags to the site to be protected.
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Begin building a simple protective barrier using standard-sized water gel bags. Allow segments of 20 minutes to transport and position 10 bags.
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It is only at this stage that you will have to transport the 15 kg bags, resulting in a total of 1500 kg for the entire operation.
Note 3 : Suggestion for transporting bags easily and safely.
Use two pails with handles. Place one bag in each pail and lift simultaneously using your legs to protect your back. This will help balance the load on each side of your body. Even when transporting a single bag, the use of a pail with a handle will minimize both the physical effort required and the risk of injury.
ALLOW 30 MINUTES TO TRANSPORT
AND POSITION 10 SAND BAGS
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Transport the sand bags to the site to be protected.
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Begin building a protective barrier. The barrier building technique may prove more challenging given the non-standardized size of the sand bags and their weight. Bag piling and positioning can also prove more difficult. Allow segments of 30 minutes to transport and position 10 bags.
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Barrier type and physical strength become important factors to take into consideration. At this stage, after shovelling 3 tonnes of sand, you must again transport and position 3 tonnes of sand bags.
Note 4 : Suggestion for transporting sand bags easily and safely.
Given bag weight, it is suggested that you use a wheelbarrow or dolly to minimize both physical effort and the risk of injury. Naturally, you will have to secure or rent the requisite equipment but the latter will prove extremely handy, especially if you must transport the bags over a considerable distance.
IMPEDING FACTORS
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Plan the purchase of Hydrogels bags and build a readily accessible inventory of the latter.
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Ensure access to a water source capable of quickly supplying a minimum of between 25 litres and 30 litres of water.
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An individual's physical condition may impact the speed at which he or she is able to erect a protective barrier with water gel bags. Carrying a 15 kg (30 lb) weight is well within the capability of the majority of individuals. However doing so repetitively can prove a little more strenuous.
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Plan the best way to dipose of hydrogels bags
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Plan the purchase and delivery of a roll of bags and closures/ties.
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Plan the purchase and delivery of the required quantity of sand. From the environmental standpoint, it is preferable to avoid waste by not ordering too much.
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Secure a location where the sand can be offloaded.
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Ensure access to tools for shovelling and cleaning up the unloading site, as well as filling and transporting the bags.
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An individual's physical strength will impact the time required to prepare the sand bags and erect a protective barrier. One must be able to lift a 30 kg (66 lb) sand bag which not everyone can do.
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Physical shape will impact both bag preparation time and erection of a protective barrier. One must be poised and able to shovel an average of 30 one kilo shovelsful of sand per bag. For 100 bags, this represents no fewer than 3000 shovelsful for a total weight consideration of 3 tonnes. Then, one will be required once again to lift this 3 tonne load of sand bags to erect the protective barrier. This works out to the equivalent of a minimum of 6 tonnes of sand that must be handled during the entire operation.
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Dispose of the bags once they have served their purpose. One must necessarily plan for the loading, transporting and unloading once again of 3 tonnes of sand bags to the most environmentally appropriate destination possible.