Sunday 26 December 2010

Pipe Dreams

If you are looking for a drainage related break  (as if !)  Desparkhotel in Austria has just the thing. They have cleverly utilised concrete sewer pipes to offer accommodation  supplied with 220V power, double bed, skylight window, decorative wall art, double door, storage space, and peace and quiet.




Ideal for any home sick drainage engineer and his spouse, not too sure if you have to sleep in full escape harness and have a gas detector set up at the side of the bed though.

There may also be a rush for the door when you hear the flush of a toilet in the far distance.






Wednesday 22 December 2010

Worker rescued after being swept through sewers

Man survives mile-long trip through Missouri sewerage system after becoming unhooked from safety line
A worker who descended into a city sewerage system on Tuesday became unhooked from his safety line and was pushed through a pipe 69cm (27in) wide for more than a mile before his calls for help were heard and he was rescued.

Daniel Collins, of Collins, Missouri, was in a critical condition at St Luke's hospital in Kansas City.
The South Metropolitan fire district chief, Randy Adams, said Collins was being treated for hypothermia and given antibiotics because he may have swallowed sewage.
Collins disappeared soon after 8am on Tuesday after descending into the sewerage system in Raymore. Adams said crews searched manholes along a 1.5-mile route near a golf course.
After about 90 minutes, a firefighter and paramedic, Antonio Smith, heard Collins calling out: "Guys, I'm down here. Can you help me?"
Smith was lowered into the sewerage chamber and found Collins about 3.6 metres down. Collins appeared to have some bruises but was able to speak, Smith told KMBC-TV.
"It was a miracle to find him in that condition," Smith said.
He said he put Collins over his shoulder, and crews topside helped lift him out. Firefighters covered Collins with coats while waiting for an air ambulance.
Adams said Collins "was not totally coherent. He was basically in and out, and he was very weak".
Collins was tethered when he descended into the sewer and was still wearing the harness when he was found. It was unclear how he became unhooked, which allowed him to be pushed through the pipe by rushing water.
Raymore officials said Collins's employer, Rosetta Construction of Springfield, was working on parts of the city's sewerage system.

Sourced from www.guardian.co.uk

Tuesday 21 December 2010

Understanding the Cause of Sewer Blockages with Exeter University

Due to low ‘visibility’, sewerage systems are inherently difficult to monitor, maintain and rehabilitate. However, in the interest of maintaining a public health barrier and preventing environmental pollution, their continued rehabilitation is essential.
Maintenance of sewerage systems is very costly and proper management is often hampered by financial constraints. As a result, a reactive ‘management by crisis’ approach is often adopted whereby maintenance is carried out as and when a service failure is reported. There is however limited scope to reduce the number of sewer blockages occurring through the sole use of reactive maintenance.
The project is being funded through the Stream IDC, an industrial doctorate centre for the water industry and is part of research collaboration between WRc and the Centre for Water Systems at the University of Exeter. The collaborative project is targeted at improving sewer operation, with the aim of the initial study being two-fold:
  1. to improve sewer performance in terms of blockage occurrence per km/yr and
  2. to reduce the total cost of sewer maintenance incurred by the sewerage undertaker.
The work will improve the way that sewerage undertakers diagnose their causes of blockage and carry out work to prevent reoccurrence. This improved methodology will be developed by achieving a better understanding of the mechanics of sewer blockage occurrence, specifically by identifying under what circumstances sewers begin to show a propensity to blockage formation.
Better understanding of the mechanics of blockage formation will improve the sewerage undertaker's ability to predict where blockages are most likely to occur and therefore manage this aspect of sewerage maintenance on a more proactive basis.
For further information contact Trefor Hillas at trefor.hillas@wrcplc.co.uk or telephone +44 (0) 1793 865089.

Sourced from Wrc plc

Monday 20 December 2010

Why Drains Block

The guys at DrainDomain.Com have put together a list of the problems typically found on domestic drainage systems.

The vast majority of domestic drainage systems in the UK are made up of 100mm and 150mm vitrified clay pipe work and for the most part these systems do their job with regard to carrying waste and storm water from one point to the next, or do they ? Most drainage systems will have some sort of defect such as misalignment of joints, stepped joints, dipped sections, fine root ingress, fracturing or leaking pipe work, but they more often than not keep on working.

This can be due to a number of reasons, drains block and clear themselves due to the weight of water that builds up in the system, other systems can operate more like a septic tank for many years given the right ground conditions with the majority of the waste water soaking into the sub-soil through defective joints while solids and waste breakdown within the pipe work.

The drainage system at the three bedroom house Grandpa and Grandma have lived in for 40 years can cope with the weekly bath and anything else they can throw at it, stick them in a nursing home and move the wife and three kids in and all the baths, showers, washing machine and dishwasher waste suddenly doubles the volume of water passing through the system and highlights any defects.

Bad Housekeeping
Many blockages are due to poor maintenance and bad habits around the property, the more serious problems don't tend to happen overnight so by regularly checking the system by lifting external manhole covers twice yearly you may not stop the final blockage but you may well see it coming prior to the big flood.

There are several things a house owner can do to avoid blockages through normal daily use a simple rule of thumb is don`t put anything into the system that will not dissolve or break down, many people seem to think that because it says disposable on the packet you can flush it down the pan and it magically disappears. Disposable nappies, sanitary goods (even the ones with wings won`t fly through the system), condoms, cotton buds and little freddie`s toy car are not designed to pass around the U bend and into the drainage system. They will of course if you try hard enough but then they are likely to stop at the first snag point and start to block the entire system.


Drainage Grids & Gullies
These are the drains at the side of the property where your rain water down spouts and kitchen and bathroom waste pipes discharge into, they should have a water trap on them similar to the way a toilet operates, the trap is there to stop smells from the main line drainage venting at ground level and the trap also prevents silt and debris from entering the system and hopefully rats coming the other way.

It is therefore good practice to get your marigolds on and clean out the gullies occasionally as grease, fat and fibres from sinks, washing machines and dishwashers can hold and solidify in waste gullies, while silt and debris from roofs and gutters collect in storm water gullies. Leaves and debris can seal the grid top preventing water from entering the gully pot so again an annual clear out could save you money in the long run as will making sure that the plates enter the dishwasher or sink with as little residue on them as is possible.


Grease And Fat
Grease and fat build up within domestic drainage systems over many years reducing the internal bore of the pipe until it eventually blocks, this can in part be avoided by being careful about the amount of grease and fat entering the system but it is virtually impossible to eradicate at source.

Dishwashers should in theory help breakdown the grease and fat due to the high temperatures they work at though i suspect that people are generally a little less careful about the amount of debris they load into the dishwasher compared to the sink.

The most common area for grease and fat to build up is in the kitchen waste gully, this is because the gully has a water trap which allows the grease to stand and cool, gullies are designed for access so they can be occasionally cleaned however armed with your marigolds and the best will in the world you will still struggle to reach the far side of the gully and its outlet. Industrial and commercial kitchens which produce large amounts of grease and fat should be fitted with a grease trap in order to comply with UK building control regs.

Blocked Toilets 
Never ever, ever use one of those toilet flush blocks that clips over the side of the toilet bowl especially if you have kids in the house, buy the ones that fit in the toilet cistern instead they are no more expensive and can`t get knocked into the toilet. Most toilet blockages are due to a foreign object being lodged in the u bend or too much paper being used, on modern syphonic toilets the syphonic action can fail causing solids and paper to hold in the pan.

More often than not when we are called to a blocked toilet it is not actually the toilet that is the problem, the problem will be outside and further down the system but the water level in the pan is affected due to trapped air within the drainage system.

Sinks, Baths and Showers 
If you allow grease, fat, rice and the general left overs from your tea enter the sink you are sooner or later going to be thumbing through a directory looking for a plumber or drainage contractor, those little pipes that leave the sink have traps and bends and usually very little fall so the debris just sits in the pipe work solidifying,

So give the plates a good scrape off before you put them in the sink or dishwasher. Soap and hair are the main causes of blockages in the bath or shower but again a little maintenance can prevent unnecessary blockages, if you see great masses of hair in the plug hole don`t poke it through take it out, you can also remove hair from traps by gently placing a small piece of shaped wire into the trap and rotating & retrieving it.

Defective Underground Pipe Work
Properties built before the 1960`s generally have vitrified clay pipes at length`s of 600/700mm, these pipes are collar and spigot with the spigot end of one pipe sitting in the collar of the next and so on, from the 1960`s onwards newer systems were jointed using rubbers sealed plastic collars and the clay pipe lengths increased , with plastic pipe work coming in 6mtr lengths. However for many years there was little if any specification with regard to pipe bedding and back fill, if there was any specification it was usually ignored and pipes were broken on installation or disturbed when back filled and as a result leak, move or collapse leading to solids snagging and blocking the system.

Broken And Fractured Pipe Work 
Vitrified clay pipe work is basically earthenware and is therefore fairly brittle, because there was no specification on bedding materials there is often settlement to some degree and if the joints hold particularly well you tend to get stress fractures, these can be longitudinal or circumferential and like a stepped joint they allow water loss, root ingress and can be snagging points, unfortunately extensive jetting of such defects can accelerate the deterioration of the system. Similarly a misplaced brick or piece of masonry making contact with the pipe when back filling would lead to a hairline fracture which in the following years developed into a major defect.

Accidental Damage To Drains
These drainage systems can lay there for decades without incident, no root ingress and little if any build up of grease and fat and then wallop !, some fool sticks a bloody great fence post through the middle of it, or builds an extension over the top or moles a new gas pipe through it. There are so many activities that go on that can affect the drainage system and more often than not the offender is not even aware there is a drainage system is in the locality, this is why you take out your Bricks & Mortar Insurance because thankfully the movement on the system beneath you drive the result of years of passing over the top with your car will be covered as accidental damage.


Tree Root Ingress
One of the most common causes of blockages to domestic systems is tree root ingress, disturbed ground such as back filled drainage trenches make easy traveling for roots and it is generally thought that condensation that naturally occurs on the outer wall of the pipe, or moisture from leaking joints attract roots looking for a good nutritious feed, though i still prefer to tell customers that the tree`s find the drains because they can here the running water inside.

The roots gain access to the system via the pipe joints, fractures, cracks and through inspection chamber walls and benching. The majority of the drainage systems within the UK are constructed from collar and spigot vitrified clay pipes, jointed using sand & cement these joints offer little resistance to fine tree roots which once inside develop into tap roots and root masses which reduce the internal bore of the pipe. More modern systems installed using rubber sealed couplings are still prone to root ingress if not protected by a root barrier or surrounded in concrete, though as modern systems are supposed to be flexible surrounding the joint in concrete is generally frowned upon.

The roots inside the pipe work cause solids to snag and build up leading to a blockage, root damaged joints leak into the sub-soil which also supports the pipe work, this leads to movement of the pipe work and more water loss, more damaged joints, more root ingress and so on.

You can read more on drain defects and how to fix them at www.DrainDomain.Com