1.00
A PPLI PPLI CATI ATI O N CRITERIA
Hunter Underground Systems
1.01 1.02 1.03
1.04 1.05
1.06
Advantages of PVCu drainpipe Pipe Dimensions Recommended minimum gradients for Foul Drains Choice of gradients Hydraulic performance performance Flow rate graphs Pipe sizing Surface water drains Graph for converting discharge units to flow rates (L/ S) Design Information General Layout Alternative pipe depth arrangements Access to Drains Access Fittings Ventilation Inspection Chambers, Access and Manhole sizing Minimum dimensions for Rodding Eyes, Access Fittings, Inspection Chambers and Manholes Rodding point system
1 .0 1 ADVA N TAG ES OF HUN TER UN PLAST PLASTICISE ICISED D PO LYV IN YL CHLO CHLO RIDE (PVCU ) DRAIN PIPE PIPE
•
Strong, lightweight material with a high resistance to aggressive soil and chemicals found in domestic sewage. The ring seal seal push fit joi nts are easily and instantly instantly joi nted, making making the syst system em ready for testing testing even in bad w eather. eather. Joints capable of absorbing absorbing significant vibration vibration and ground movem movement ent without joint failure. Flexible lexib le joints ensure ensure that they remain watertight under under working worki ng conditions to to prevent pollution poll ution of the surrounding ground. gro und. Designed Designed so that that nothing nothing in the pipes pip es,, joi nts or fittings projects into the pipeline pi peline to cause cause an obstruction. obstruction. The smooth smooth bore prevents particles par ticles clingi ng to the the internal internal surface, surface, reducing the accumulation accumulation of solid solid s within wi thin the the drain. The smooth bore aids aid s higher velocity, which whi ch permits permits shallow er falls and therefore therefore less less excavation. The infrequent joi nts and smooth smooth internal bore result result in lower turbulence and increased hydraulic hydra ulic performance thus thus considerably reducing the possibilities of a blockage.
• • • • • • •
Identification Identification pointers Colour: bronze/ golden brown Lengths: 3m and 6m plain or single socketed ends. British Standards: Hunter Plastics Ltd pipes and fittings are produced in accordance with BS EN 1401-1: 1998 whilst all ancillary fittings and pipes are manufactured in accordance with BS 4660: 2000.
1.02 PIPE DIMENSIONS N OM O M IN IN AL AL DI A M ET ETER
M IN IN
M AX AX
W A LL TH I CK N ES ESS M IN IN
W EI EI G H T KG / M (M EA EA N )
1 1 0 mm (4 i n)
1 1 0 .0 mm
1 1 0 .3 mm
3 .2
1 .6 5
1 6 0 mm (6 i n)
1 6 0 .0 mm
1 6 0 .4 mm
4 .0
3 .2 4
2 0 0 mm (8 i n)
2 0 0 .0 mm
2 0 0 .5 mm
4 .9
4 .9 6
2 5 0 mm (1 0 i n)
2 5 0 .0 mm
2 5 0 .5 mm
6 .2
7 .0 2
3 1 5 mm (1 2 i n)
3 1 5 .0 mm
3 1 5 .6 mm
7 .7
1 1 .1 0
Design of Drainag e or Sew Design Sew era ge Systems Systems The designer of any drainage or sewerage system should make themselves fully conversant with the following, Approved Document H of the Buil Buildi ding ng Regula Regulatio tions ns (Engla (England nd & W ales). Technical echnica l Stand Standard ards s Part ar t M of the Build Building ing Standard tanda rds s (Scotla (Scotland) nd) Regulations. Technical Booklet N of the Buildi Buildi ng N of the Buildi Buildi ng Regulations Regulations (Northern (No rthern Ireland). BS EN 75 2: 19 98 the Briti Britis sh Standard for Drains Dra ins and Sewers outs outside id e Buildi Buildi ngs. Sewers Sewers for Ad option optio n by the Water Services Ass Association/ ocia tion/ W Rc. Standard Specification pecifi cation for fo r W ater and Sewerage Schemes chemes,, (Scotland) (Northern (N orthern Ireland). Pipe Sizing and Gradients The table below lists the minimum pipe sizes and gradients to prevent sedimentation build up and blockages in foul drains. However, where the length of the drain or sewer that serves a small number of properties is very long the steeper gradient could be considered. Also, where the ground is expected to settle steeper gradients should be used to compensate for the eventual settlement. Conversely flatter gradients can be achieved when the standard of design and pipe installation is high.
1.03 RECOMMENDED MINIMUM GRADIENTS FOR FOUL DRAINS PEA K FLO W ( LI TRES/ SEC)
PI PE SI Z E (mm)
M I N I M U M G RA DI EN T
7 5 ++
1 :4 0
100
1 :4 0
7 5 ++
1 :8 0
100
1 :8 0
150
1 :1 5 0 +
<1
>1
N otes: otes:
Mi nimum m of 1 W C. * Minimu
+ Minimum of 5 W Cs. Cs.
*
++ N o W Cs. Cs.
The above table sets out the minimum gradients for foul drains as recommended in approved Document H1 of the Building Regulations 2002 and BS EN 752-4: 1998.
1 .0 3 CON TIN UE UED D - CHO CHO ICE O F GRADIEN GRADIEN TS
Choice of gradients should be such as to maintain self-cleansing velocity under normal discharge conditions. To achieve achi eve a satisfactory satisfactory ins i nstalla tallation, tion, diamet di ameter er and grad g radient ient should should be adequate a dequate for the maxi maximu mum m flow and a nd competent supervision should be provided to ensure a high standard of pipe quality, laying, jointing and workmanship. This is particularly important when pipes are laid to flat gradients. The following guidelines on gradients should be observed. (a)
For flows flow s of less less than 1 L/ L/ s, s, pi pes not exceeding exceeding 1 00 mm nominal bore bo re at gradients grad ients not flatter than than 1: 40 have proved satisfactory.
(b)
W here the peak flow is more more than than 1 L/ L/ s, s, a 1 00 mm nominal nominal bore pi pe may may be laid at a gradi ent not flatter than than 1 : 80 , provided pro vided that at least least one W C is connect connected. ed.
(c) (c)
15 0mm nominal nominal bore pipe maybe maybe laid at a gradient gradi ent not flatter flatter than than 1:150 1:1 50 , provided that that at least least five five W Cs are connecte connected. d.
(d)
Experience xperi ence has shown shown that for gradi gr adi ents ents flatter than thos those e given in item i tems s (a) to to (c), a high hig h standard standard of desig design n and workm wo rkmans anship hip is neces necess sary ar y if i f blockages bl ockages are to be minimis mini mised. ed. W here this this has been been achieve achi eved, d, gradients of 1:130 for 100mm nominal bore pipes and 1: 200 for 150mm nominal bore pipes have been used successfully.
W here the the availab avai lable le fall fal l is i s les less than than that neces necessary ar y to achieve a chieve the the recommended recommended gradi gr adi ent, ent, i ncreasing ncreasing the pipe pip e diameter particularly at low flows is not a satisfactory solution. It will lead to a reduction in velocity and depth of flow and an increase in the tendency for deposits to accumulate in the pipes. W here it is expected that a drain dra in may be b e affected by settlement, settlement, the selected gradi gra dient ent should should be b e such such as to ensure that a satisfactory fall will be maintained. Research has shown that high velocities of sewage flow arising from steep gradients do not cause increased erosion of pipes or deposition of solids. In such situations drains should be laid at gradients which are the most economical in excavation and cost. High velocities can, however, cause excessive turbulence at bends and manholes and lead lea d to fouling. fouli ng. W here this this occurs occurs it can be mitigated mitig ated for example by using long radi r adi us or sealed access fittings.
Hyd ra ulic ulic Perform Perform a nce nce Various roughness values (k or K s) s) for drain pipe are suggested by the industry, the commonest being 1.5mm, 0.6mm and 0.06mm. BS EN 752-4: 1998 recommends k values for foul and combined drains and sewers in average condition condi tion of I.5mm I.5 mm and 0 .6mm .6 mm depending dependi ng on the velocity of flow. W hilst it recommends recommends k 0.6mm for surface water. The smooth bore of PVCu drain and the infrequent joints result in lower turbulence and increased increased hydraulic hydrauli c performance. per formance. Consequently Consequently Hydraulic Hydra ulic Research esearch Ltd Ltd i n their ‘ TabIes for the Hydrauli Hyd raulic c Design of Pipes and Sewers’ recommend Ks 0.06mm for PVCu pipe with ring seal sockets at six to nine metre intervals. Flow Rate Gra phs The flow rate graphs on the following pages are for full bore flow and although public and trunk sewers are often designed to run full during periods of calculated peak loading, it is recommended that estate drainage and drains close to buildings should be designed to run part full. Therefore, a proportional depth should be selected to allow for additions to the system, however, to ensure that trap seals are retained, foul drains and sewers should not exceed 0.75 proportional depth.
W hen cons consid idering ering the flow rate ra te one should should remember remember that that a pipe pi pe flowing flow ing half ha lf full would wo uld dis di scharge half the full bore capacity at the full bore velocity, however, there is no direct relationship between other proportional depths. Pipe sizing Foul drains
The generally accepted method of sizing foul drains serving individual or small groups of buildings is the discharge unit method. Discharge units for various sanitary appliances discharging to System III discharge pipes are given in table 1.01. Surface Water Drains
The drain should be sized to provide sufficient storage as protection against flooding and surcharge from storms of predetermined intensities and frequencies. For calculating the run off from roofs, and paved areas of up to 2000 m2 use the formula Q = Ae x IF x RI 3600 Q = run off in litres per second Ae = effective effective area in m2 IF = Impermeability factor (The worst instance is covered using a factor of 1.0 see BSEN 752-4 for further information) RI = rainfall intensity (use 50mm/ hr for paved areas and 75mm/ hr for roofs) 1 .0 4 Conver ting Disc Discha rge Units to Flow Flow ra tes (I/ (I/ s)
Discharge units are figures used for calculation purposes only and are not related to the discharge rates quoted in product standards. The method attributes discharge units for the sanitary appliances, which can be converted to the flow (in litres per second) by using the formula below. Q = k DU The quantity of water (Q) The frequency factor (k) The square root ( ) The sum of all the discharge units (DU DU))
BANANA GRAPH
1.0 0.9 0.8 0.7 h t p e D l a n o it r o p o r P
Discharge
0.6 0.5 0.4 0.3
Velocity
0.2 0.1 0 0 .1
0 .2
0 .3
0 .4
0 .5
0 .6
0 .7
0 .8
0 .9
1 .0
Proportional Velocity and Discharge
DIAGRAM SHO W IN G PROPORTIO PROPORTIO N AL DE DEPT PTH H
D
d
Proportional Depth
d D
1 .1
1 .2
Fi g. 1
Tab le 1. 01
System ystem III Disc Dis cha rge Units Litres per second second 0 .3 1 .3 0 .2 0 .6 1 .2 1 .3 0 .4 1 .3 0 .4 0 .2 (i ) 1 .2 -1 .7 (i i ) (i i i ) 1 .4 -1 .8 (i i ) (i v) 1 .6 -2 .0 (i i ) (i v)
Ap plia nce nce W ash Hand Basi n, Bi det Ki tchen Si nk Di shw asher Domesti c Domesti c W ashi ng M achi ne up to 6 kg Commerci al W ashi ng M achi ne up to 1 2 kg Bath Show er Tray w i thout plug Show er Tray w i th plug Bow l Uri nal Uri nal Stall W ater Closet 6 .0 li tres W ater Closet 7 .5 li tres W ater Closet 9 .0 li tres i. per person ii . with wi th siphon ip hon flush flush cistern cistern only ii i. since January 2 0 01 this is the the maxi maximu mum m flush flush allow ed for a newly install installed ed W C suite suite iv. only use use to replace the same siz size e sip siphon hon Ta b le 1 . 0 2 Fr e q u e n cy o f u se o f a p p li a n ce dependent upon the type of building Intermi ttent use, dw elli ng, guesthouse, offi ce Frequent use, hospi tal, school, restaurant, hotel Conges gested use, toile ilets and and showe owers open pen to the publ public ic Speci al use, laboratory bui ldi ngs
k
0 .5 0 .7 .7 1.0 1.0 1 .2
Ex a mp le of Ca Ca lcula lcula ting Proportiona l Flow Flow Usi Using ng The The Flow Flow Ra te Gra phs We wish to discharge to foul water drains from thirty-four two bed terraced houses containing. A p p lia n ce Ki tchen Si nk Domesti c W ashi ng M achi ne up to 6 kg Bath W ater Closet 6 .0 li tres W ash Hand Basi n TO TA L f o r o n e tw o b e d te r r a ce d h o u se s TO TAL fo for thi rty-four tw o bed terraced houses
Q = k DU
Disch a r g e U n its 1 .3 0 .6 1 .3 1 .2 -1 .7 0 .3 5 .2 1 7 6 .8 .8
Q = 0.5 17 6.8 6. 8 DU transpos transposes es to a flow rate of 6.6 5 l/ s
I n te r m itte n t u se f a cto r
0 .5
The flow rate ra te graphs on the the following follow ing p ages are for full bore flow. flo w. W hen pipes are desig designed ned for less less than full capacity, the proportions of velocity, discharges and depths are shown on the banana graph. The Hydraulic Hydra ulic Res Research earch Tables abl es state state that for a velocity of approxi app roximate mately ly 0 .75 .7 5 m/ s we w ould select a Ks0 Ks0 .6mm .6 mm for PVCu pipe in a normal slimed condition. Reading from the Ks 0.6 graph we find that a 110mm diameter pipe flowing full bore will carry 8.0 l/ s at 0.84m/ s when laid at a gradient of 1.65. Refer to the banana graph to see that where the proportional depth line of 0.7 strikes the discharge line we have a reading of 0.86 on the bottom of the banana graph. Therefore a proportional discharge factor of 0.86 x 8.0 l/ s (the full bore flow) = 6.88 l/ s W here the the proportional d epth line of 0.7 strikes trikes the the velocity velocity line we have a reading of 1 .11 .1 1 on the proportional velocity and discharge line of the bottom of the banana graph. Therefore a proportional velocity factor of 1.11 x 0.84 m/ s (the full bore flow) = 0.93 m/ s 110mm dia. pipe laid at 1:65 will carry 6.88 l/ s flowing at a speed of 0.93 m/ s.
2000
1000
)l l u f g n i n n u r( s / s e rt il e g r a h c s i D
10 0
10 9 8 7 6 5
10
40
100
5 00
1000
Gradient 1 : x Discharge rate of PVCu drain/ sewer pipes in the nominal range from 110 to 630 for different gradients based on a roughness height of 0.06mm. Suitable for PVCu pipe with ring seal sockets at 6-9m intervals
2000
1000
)l l u f g n i n n u r( s / s e rt il e g r a h c s i D
10 0
10
10
100 Gradient 1 : x Ks 1.5mm only required for UPV-C sewers in a poor slimed condition.
1000
6 7 8 91
2
3
4
5
6
2
7 8 9 1
3
4
5
6
2
7 8 9 1
3
4
5
6
Roughness Ks 0.6mm
N ITY EA C / s M LO 0 m E V 4. 3.
1000
/s m 0 2
.
/s m 5 2.
/s m 0 1
5 .7
/s m 1.
/s m 5 2 1.
/s m 5 1.
/s 0m 0.
/s m 9 0.
s / s e rt il e g r a h c s i D
7
/s m 5 0.
/s m 6 0.
/s m 5 NOMINAL SIZE
6
3 0 m m
10 0
5
0 0 m m
4
0 0 m m
3
1 5 m m
2
10 9 8 7 6
5 0 m m
2
0 0 m m
5 4 1
6 0 m m
3 2 1
1 0 m m
1 6 7 8 91
10
2
3
4
5
2
6 7 8 9 1
100
3
4
5
6
7 8 9 1
10 0 0
Gradient 1 : x Ks 0.6mm suitable for UPV-c foul water sewers in a normal slimed condition
2
3
4
5
6
1.05 DESIGN INFORMATION General layout The layout of drains should comply with the relevant Buildings Regulations and British Standard Codes of Practice listed previously under ‘ Design of Drainage Systems’ . The following is intended as a guide only. The layout of any drainage system should be as simple as practicable. The following detailed design considerations apply to all drains. A drainage system must be planned and laid in such a manner that effluent is conveyed from the house to the sewer, cesspool or other places of disposal as speedily as possible and without causing an unacceptable nuisance, or danger to health. Drains must be constructed so as to be as far as possible self-cleansing and so reduce the risk of blockages of a minimum, whilst adequate mans of access must be provided for the purpose of inspection, testing and clearing should an obstruction take place. Drains must be watertight to prevent pollution of the surrounding ground by soil wastes, and adequate ventilation is essential. Principles to be Observed in the Design of a Drainage System The following are the main points which must be considered in designing a drainage system:1.
Pipes ip es to be laid at such a gradi ent as to ensure ensure a selfself-cleansing cleansing velocity. See section 1.03
2.
Pipes ip es to be of sufficient size iz e to cope effectively effectively with wi th the maximum load to be carried. carri ed. See section 1.03
3.
Efficient mans of ventilation ventilation to be provided and maintained. maintained. See following pa ges
4.
Adequate Adeq uate means of access access to be provided. provi ded. See See next web pag page e
5.
Length ength of branch drains to be kept to a minimum minimum and all junctions junctions to be made in the the direction direction of the flow. See Tab Tab le 1 .0 3
6.
Pipes ip es to have watertight watertig ht joints joi nts.. See sec section 6.0 4 - 6 .06
7.
Every part par t of the drai nage system ystem to be adequately supported. uppor ted. See section 6.08
8.
So far as circumstances circumstances will wi ll permit, drains should not pass under buildings. build ings. See section 8.13
9.
Drains to be laid as a s far as possible possible in straight straight lines lines between between points where acces access s is provided
10 .
Drains not to to be laid i n close close proximity to to trees trees owing to the possibi possibility lity of damage being caused caused by roots. roots.
Access to drains The Hunter Underground range offers many different types of components for gaining access to drains: 230mm diameter Shallow and 450mm diameter full height Inspection Chambers, Sealed Rodding Access Fittings, Manhole Bases, Gullies and, within traditional manholes, Channel and Sealed Access Fittings. Full details of these products are given in Section 2 (page 17). Access is required to drainage installations for testing, inspection, maintenance and the removal of debris. Access to drains allowing rodding in both directions can be provided by either manholes, or pre-formed inspection chambers, and by some access fittings. Rodding eyes provide access in only one direction. Every section of drain or sewer should be accessible without entering buildings. Siting of access points Access should be provided at the following points: a).
on or near near the the head head of each each drain run
b).
at a change change of gradient gradient or alignmen alignmentt
c). c).
at a change change of pipe size
d).
at a junction junction (see (see note 1) or at a bend (see (see note 3)
e). e).
at drainage fittings fittings such as intercept intercepting ing traps or antianti-flood flood valves valves
Notes: 1.
W here a branch joins a main pipe without without an inspect inspection ion chamber chamber or manhole manhole at the the junction, junction, access access should be provided on the branch within 12m of the junction.
2.
Deep inspection Deep inspection chambers may restrict restrict the the use use of trenchles trenchless s technolog technology y equipment and should should not be used used in highways highway s or other high use areas when excavation for repairs would be unacceptable.
3.
On drains drains, bends bends with an angle of not more more than than 45 ˚ may be used used outsid outside e inspection chambers. chambers. W here bends occur outside manholes and inspection chambers, this may restrict access for CCTV surveys.
The table below indicates the recommended maximum distances between access points. These are based on manual cleaning techniques, consequently where only remotely operated and automatic equipment will be used for maintenance (e.g. jetting), the spacing may be increased. Table 1.0 3 Distance Distanc e from: fr om:
To access acc ess fi tti ng Type 1
To access acc ess fi tti ng Type 2
To j unction uncti on or branch
To i nspection nspecti on chamber shallo allowe werr than 1 . 2 m
To manhole manhol e and i nspecti on chamber ber dee deeper per than 1 . 2 m
Hunter 2 3 0 mm Shallow Access chamber Start of external drain *
12 m
12m
_
2 2m
45m
Roddi ng eye (DS6 7 0 )
22m
2 2m
22m
45 m
45m
A ccess fi tti ng Type (1 )
_
_
12m
22m
2 2m
_
_
45 m
22 m
45m
shallow er than 1 . 2 m
22 m
45m
22 m
4 5m
45m
M anhole & i nspecti on
_
_
_
4 5m
9 0 (Up to 2 0 0 m
min. 150mm dia. A ccess fi tti ng Type (2 ) min. 225mm dia. Inspection chamber
chamber deeper
for man-entr y
than 1 .2 m
si ze drai ns and sewers - see BS EN 75 2-3:19 97
* Note: Soil stack or ground floor appliance
Access fittings Access fittings Type 1 and 2 are drain dr ain fi ttings that have an opening on to the pipe, w hich is wid ened into a small small chamber cap able of being fitted with a cover. The chamber should preferably be the same size as the drain pipe but should not be less than 100mm diameter. An example of a type 1 access fitting is Hunter ’s access pipe DS309, or access junction DS680 which can be installed within a chamber with a cover at ground level to provide a sealed drainage system. An example of a type 2 access fitting is Hunter’s shallow access chamber DS71 Risers DS72 and Frame and cover DS69. The diagram below illustrates principals taken from the taken on the previous page. Hunter ’s rest bend (DS663) must always be used at the base of a soil stack with a type 1 or 2 access fitting within twelve metres because British Standard 752.3: 1994 states ‘ every drain and sewer length should be accessible for maintenance and cleaning without the need to enter buildings ’ . However, should the property owner need to unblock the underground drain within the property ’s curtilage an access fitting at the bottom of the soil and vent pipe will allow a set of drain rods to be passed easily through to Hunter ’s shallow access chamber where any debris can be removed.
Access pipe S309
Type 2. Shallow access chamber base (DS71) Shown with 2 no. raising pieces (DS72)
Bedding/ backfill materials
Rest bend DS663
Bedding/ backfill material to Appendix A of BS5955
Main drain
Ventilation of the underground drainage system All drainage systems need adequate ventilation to the open air in order to reduce the build-up of toxic or explosive gases in the system, and to equalise air pressure when effluent flows through a pipe. In order to ensure the drainage system is ventilated by a flow of air, a vent pipe or soil and vent stack should be provided at: 1)
the the head head of each each main drain
2)
a drain fitted fitted with an interce interceptin pting g trap
3)
any drain subject ubject to surcharge urcharge
Ventilation contVentilating pipes open to outside air should finish at least 900mm above any opening into the building within 3 metres, and should be finished with a vent cowl. All inlets entering a foul water or combined drainage system must be trapped with a sufficient depth of seal to prevent syphonage. This includes all yard gullies, rainwater and surface water inlets. Drains carrying surface water only do not usually need traps. Inspection chambers, access and manhole sizing The depth of any inspection chamber or manhole is determined by its minimum internal dimensions, since there must be adequate access or entry for rodding and maintenance. Minimum dimensions for rodding points, access fittings, and inspection chambers (non man-entry) Table 1.0 4 Recommended dimensions for rodding eyes, access fittings and inspection chambers (non man-entry) Minimum nominal internal dimensions1 Type ype of acce acces ss
Dept Depth h to inve invert rt from from cove coverr leve levell
Roddi ng point
Circu Circular lar diam diameter eter
Clear opening
Remarks
(m)
Recta ectang ngul ular ar leng length th and wi dth (mm)
-
-
Preferably same si ze as drain but not less than DN100
-
Same si ze as pi pew ork4
(mm)
Recta ectang ngu ular leng length th and w idth (mm)
Circu Circula larr diam diameter eter (mm)
Access fitting2 Type (1 ) See Ta bl bl e N B. B. 1
0 . 6 or less, except wh where si tu tuated i n cha mb mb er er
150 x 10 0
150
Same size as access fi tttti ng ng4
Same si ze as access fitting4
Access fitting2 Type (2 ) See Ta bl bl e N B. B. 1
0 . 6 or less, except w here si tuated i n cha mb mb er er
225 x 10 0
225
Same size as access fi tti ng4
Same si ze as access fitting4
Inspection chamber3 shallow
0 . 6 or less
225 x 10 0
-
Min 19 0
1 . 2 or less
450 x 45 0
450
Min 430 x 4 30
Min 43 0
G re reater tha n 1 .2 .2
4 50 50 x 4 50 505
450 5
M ax 3 0 0 x 3 0 0
M ax 3 5 0
Inspection chamber4 deep
N otes: otes:
1 9 0 for drai ns up to DN 150
The depth restriction is imposed because of the limited access afforded and is based on the ability to manipulate a stopper at arms length from the surface
Restricted to inspection and remotely operated equipment - no personnel entry Restricted to inspection and remotely operated equipment - no personnel entry. Max size imposed to prevent personnel entry.
1
These hese sizes iz es app apply ly to strai straightght-through through pip es, es, larger larg er sizes iz es may be required for turning chambers or chambers with several side branches.
2
Fitting wi th a removable cover cover that permits access access into the pip e, either from surface surface level level or from within a chamber.
3
Chamber with a removable removable cover constructe constructed d on a drain drai n or sewer sewer that provides provi des access access from surface surface level only, but does not permit entry entry of a person (BS (BS EN 75 2-1).
4
The clear clear opening may may be reduced reduced by 20mm in order order to provide proper support support for the the cover cover and and frame. frame.
5
It may not be possibl possible e to to gain gai n access access to sid side e branches. branches. The The upper upper part pa rt of the the chamber chamber may be reduced reduced to a minimum of 300 x 300 or 350 dia. to form a shaft.
Hunter Hunter Plastics Plastics Limited only manufacture manufacture preformed pr eformed inspection chambers that provid e access from ground gr ound level, b ut do not permit entry of a person (non-man entry). Hunter does manufacture products that can be used within manholes that accommodate man entry, such as channel pipe, channel bends and Type 1 access pipe and junctions. For the recommended dimensions of these manholes manholes refer refer to Table N B3: BSEN 75 2:3 . 1 99 7.
TYPI CAL DRAI DRAIN N LAYO UTS SEPARATE SYSTEM
SVP
SVP
SVP
SVP
IC BIG
SVP
SVP
IC BIG
BIG
RW P RW P
SA C
IC BIG
BIG
RW P RW P
SA C
BIG
RW P
RW P
SA C
IC
CO M BIN BINE ED SYSTEM This diagram shows the variety of ways Hunter drainage products can be utilised to make the same connections.
RP SAC
BIG
IC
BIG BIG
TG
TG IC
BIG
BIG
BIG
BG
BG IC
TG
TG IC
KEY Trapped rap ped Gully Gull y Rodd i ng Poi nt Inspecti on Chamber Shallow A ccess Chamber Soi l Vent Pi pe Back Inlet G ully Bottle G ully Rai nw ater Pi pe
TG RP IC SA C SVP BIG BG RP
Drainage layouts shown are for guidance purposes only. All drainage schemes should comply with local authority requirements.
1.06 RODDING POINT SYSTEM Head of Drain Access Rodding points eliminate the need for the majority of conventional manholes. However, there are obviously certain cases where these are unavoidable or are required by local building control regulations. Using the standard range of Hunter fittings, various combinations of rodding points may be formed - a number of these are illustrated in the next few pages. By using this method of installation considerable savings may be made over the traditional form of manhole construction. The Ramped Rodding detail shows a method of using the DS22 sealed plate access point in the DS3 square hopper. However, the DS22 can be directly solvent welded onto the pipe end. The following details provide a vandal-proof access but should only be situated in paths or borders, as the DS22 or DS670 are not designed for heavy loads.
Rodding Point System Shallow Rodding Point
DS670
DS676
110mm Rodding Point
Rodding Point System Rodding Point for Deeper Inverts DS670
DS208
DS211
DS557 DS211
Rodding Point System Ramped Rodding Point
DS22 sealed plate solvent welded to square hopper DS3
45 ˚ bend DS331
45 ˚ branch DS678
Suitable backfill material
110mm pipe to suit length
45 ˚ bend DS331 or DS676
Rodding Point System 45 ˚ Swept Junctions are used for blind connections on drain runs
DS331 DS678
Blind connection to 110mm drain (plan view)
Rodding Point System
The lay outs below illustrate illustrate the savings that m ay be m ad e using using the Rodding Point Point System. System. TRADITION ADITIO N AL SYST SYSTEM W ITH ITH MAN M AN HO LES Using a traditional manhole system extra time and labour costs are spent on unnecessary excavation and installation. Manholes require either precast concrete rings or a concrete base with a engineering brick chamber to be constructed, then drainage channel needs to be haunched and covers and frames need to be set in position. MH
MA IN SEW ER SURFA CE WATER W ATER DRAI DRAIN N MH
MH
MH
MH
MH
MH
MH
MH MH RW Gully
SVP
RW Gully
SVP
SVP
SVP
RW Gully
SVP
RW Gully
MH
MH
Rodding Point System Using the rodding point system deep excavation is not required. Swept 135 ˚ junctions are installed on the drain branches and the main drain run with rodding points fitted at ground level. An inspection chamber or manhole must be fitted in the system to allow debris to be removed from the system. Otherwise, eliminating extra time and labour costs on unnecessary excavation and installation makes savings. MH MA IN SEW ER SURFA CE WATER W ATER DRAI DRAIN N MH
MH
MH RP
SVP
RP
RP
RW Gully
SVP
SVP
RW Gully
RP
RW Gully
SVP
RP
SVP
RW Gully
RP MH
