Here are two key questions:
The answer to the first question is implied. The uninformed consumer is expected to accept the certification of an approved sample of the product as a better than nothing.
All official tests standards whether BS or Kitemark or International are limited because the results are strictly only applicable to one or a range of "typical" samples that was tested: there is an assumption that other similar products could perform in the same way but no guarantees.
The actual condition of the product(s) when used, and whether or not the real-life conditions are more demanding than the test conditions, affect the test results and real life performance.
Specific to flood product tests to BS 851188 2019 the tested product must stand alone. Flood Traps would need to be tested complete with your door and frame in an approved and certified test facility.
Since valid results would be dependent on the condition of the building structure (your door and its frame and how well they are fitted in the building) in addition to DIY product Flood Traps obviously cannot be covered by any standard, so are deemed to be beyond the scope of BS 851188 or any other similar standard.
You could think about it this way. National authorities / governments tax incentivised Diesel engine vehicle purchases and reduced the tax on diesel fuel to convince us to buy a diesel-powered vehicle consuming less than petrol and emitting less greenhouse gas overall. ‘Great,’ we thought, ‘who wants to damage our climate when we can do better and save money?’
The World Health Organisation, EU and the British government later decided that diesel fumes included unhealthy particulate matter – so they kept upping the exhaust emissions standards.
Finally, we discovered test results to standard tests were not in line with expectations. Further investigations revealed a loop hole in the standards that car manufactures were using to establish lower fuel consumption figures than were achievable in real life.
Did you ever have a car that consistently consumed the published miles per gallon or litre/100 km, consuming precisely the advertised number of Litres or Gallons of fuel manufacturers and government approved certified test facilities claimed?
In real life natural wear and tear, poor maintenance, and the way the products are actually used make the results unreliable.
Test standards are limited; they test a new product in pristine condition under very specific laboratory-controlled conditions so they supply best case scenario results, not real world results which are unpredictable by definition - know one knows what the future will bring.
Governments can also give different levels of importance to the range of results to suit their policies: as we saw in the case of diesel-powered vehicles authorities intervened in the market by subsidizing & promoting diesel fuel and cars - with lower road tax and less tax on the fuel itself.
In the case of flood products, the British government free issued sandbags via councils and are now over correcting that mistake by exclusively promoting and subsidising government approved (British Standards or Kitemarked) products.
The Corona Virus and the car industry have taught us scientific modelling is never exactly the same as real life with all its complexities and unforeseeable variables: it is up to us as individuals to use our common sense to come to an informed decision on what is best for us, within budget and proportionate to the risks and potential outcomes.
A CE or BS or Kitemarked or any "proven" protection product; if not in pristine condition and used precisely as in test laboratory conditions is as likely to perform differently in real life as one that has not been tested and certified to work under specific test conditions.
Question 2. What are the benefits, or disadvantages, of restricting choice to products the government and standard tests imply are worthy of your attention and money? What does it mean to you and me?
The alleged benefit is that product sold to do a job are more likely to do it if tested to a standard. As explained above the buyer should beware that this is virtually never 100% true. Of course, some tests like for airplanes are so stringent that they should never fail in real life – then again even they fail – remember the Boeing 737 Max.
Standard tests give more consistent results. Perhaps, but remember the tests are created by experts using the best available technology and knowledge. Since neither the experts, the technology or the knowledge is perfect we should be wary of falling into the false sense of security trap.
Tests by default are designed to test old ideas, new ideas and better ways of solving a problem often fall outside the scope of the test – just as Flood Traps do – and have to be “supported” by old / existing technology to be made suitable for the test.
All this expertise and fiddling around to create tests cost money and the bottom line is that tested products have to be funded by higher prices.
Did you know that fewer than 1 in 3 people who have actually been flooded invest in any kind of flood protection?
Do you think it might have something to do with the cost of flood protection?
If you restrict your choice to the government & council promoted / endorsed CE, BS Kitemarked flood mitigation products, you could talk yourself out of taking any action to be prepared - their solutions are generally costly, involve a lot of work to choose, fit, and maintain and to use when floods are forecast. They can be a constant reminder that you are at risk of flooding and an unwanted advertisement that your property is prone to being flooded.
On the other hand, it is prudent to take some action to reduce the cost and heartache of being flooded. Since Sir Micheal Pitt told the British government he could find no evidence that Sandbags are effective for household use if you really don’t want to invest big time in certified flood protection, at least get some DIY Flood Traps in to help reduce the flow of flood into your property through usually essential gaps around doors and windows.
Flood Traps for your doors and low-level windows provide easy-to-use, effective protection. Even though authorities cannot endorse them and they cannot be tested to British Standards they perform very well all the same and are certainly much better than sandbags or doing nothing to keep floods from getting into your property through gaps around doors and windows.
Using Flood Traps as one of a range of flood mitigation products, could be the best low cost investment you ever make.