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U.S. Patent # 6074130; Canadian Patent # 2269565

All RELINER products are proudly made in the U.S.A.


RELINER® / Duran Inc.
9 Matthews Drive, Unit A1/A2
East Haddam, CT 06423
Phone: (800) 508-6001, (860) 434-0277
Fax: (877) 434-3197


Basic Application: RELINER® INSIDE DROP SYSTEM is a plastic composite collection device that facilitates the controlled drop of effluent into the main stream flow of a sanitary manhole. The Drop Bowl permits easy inspection and cleaning without the need to enter the structure. The custom made adjustable stainless steel straps fully support the drop pipe. 

Advantages of the INSIDE DROP SYSTEM by RELINER®:

  • Reduce maintenance
  • Eliminate confined space entry
  • Speed Inspection
  • Simplify cleaning
  • Reduce turbulence and odor
  • Solids and liquids remain together
  • Erosion of structure eliminated
  • High corrosion resistance
  • Allow workers to enter structure without risk of effluent contact
  • Increase pump life in wet wells

Composition and Materials: RELINER® DROP BOWL is hand fabricated from marine grade fiberglass. The clamping pipe supports are of 304 stainless steel with 18-8 stainless nuts and bolts.  316 stainless is also available.

These materials have extremely high resistance to sewer acids while providing very smooth, low maintenance assemblies.

The open design allows for grade level inspection and cleaning while containing the incoming material and conducting it smoothly into the main flow of the system.

The RELINER Drop system is compatible with virtually all types of manhole construction and rehabilitation technologies and materials.


RELINER© INSIDE DROP components consist of

  1. Composite Drop Bowls
  2. Stainless steel clamping brackets

RELINER composite components are hand and chopper gun laminations of these properties:

Physical Properties of Unsaturated Polyester Resin Reinforced Laminates
( 33 / 66 Glass / Resin 1.5 oz mat Laminates .125 in. ) Flexural Strength (psi) ASTM D-790 27,100 Flexural Modulus (psi) ASTM D-790 1,157,000 Tensile Strength (psi) ASTM D-638 16,700 Tensile Modulus (psi) ASTM D-638 1,457,000 Tensile Elongation (%) ASTM D-638 1.54 Hardness, Barcol 934.1 ASTM D-2583 55 - 60


Physical Properties of ISO Gel Coat Room Temperature Cured for 45 hours Post Cured at 50° for 24 hours Tensile Strength 6,218 6,581 Elongation, % 2.70 1.90 Flexural Strength, psi 11,363 11,329 Heat Distortion, °F 0.544 x 106 0.713 x 106 Mandrel Flex, Mandrel Diameter in Inches - 1.0

Stainless steel clamping bracket materials:

  • 304 series non-magnetic stainless steel - 11GA
  • 18-8 series non-magnetic stainless steel 3/8 x 18
  • 316 Stainless also available

Sample Specification for RELINER® INSIDE DROP SYSTEM:
All new and / or existing manhole structures employing inside drops shall use RELINER Inside Drop Bowl components as produced by RELINER® / Duran Inc. 9 Matthews Drive, Unit A1/A2, East Haddam, CT 06423 (800) 508-6001, fax (877) 434-3197 or equal.  Bowl size shall be determined by incoming pipe sizes and flow rates. The bowl shall be installed as per manufacturer's instructions using stainless steel fasteners. The appropriately sized drop pipe of SDR 35 PVC, Schedule 40 or other shall be securely attached to the manhole wall using stainless steel RELINER Adjustable Clamping Brackets and stainless steel fasteners. Bracket interval shall be 4 feet maximum (minimum of 2 brackets). The connection of Drop Bowl to drop pipe shall be by flexible external pipe coupler. The turn-out at the base end of the drop pipe shall be accomplished with an appropriately angled PVC pipe elbow (45 degree recommended). RELINER is manufactured by Duran Inc.,


1. Select Drop Bowl of size appropriate to flow rate and pipe diameter. Examples: 
(The"A" Bowl with 4" outlet will service up through full 6" inlets. The "A" Bowl with 6" outlet will service up through full 8" inlets. Can be used for 10" & 12" inlet moderate flows. The "B" Bowl with 8" outlet will service up through full 10" inlets. The "B" Bowl with 10" outlet will service up through full 12" inlets. Can be used for 15" and 16" moderate flows. Larger sizes and flat wall configurations are also available.)

2a. Trim incoming pipe so that only 2" maximum protrudes into manhole.

2b. For improved flow control, cut a "V" shaped notch at bottom edge of incoming pipe.

3. Center Drop Bowl directly under incoming pipe, allow approximately 1" clearance between pipe and bowl.

4. Attach Drop Bowl to manhole wall with 3/8" diameter stainless steel bolts in lead expansion anchors. (See following instructions).

NOTE: A & B Bowls are best installed with (4) 3/8” expansion anchors.  24 & 30 Bowls are best installed with (6) 3/8” expansion anchors.   36 & 48 Bowls require (8) & (10) respectively 3” Wedge Anchors. 

NOTE: Fiberglass Manhole Installation Requires Special bolts!!!!!! See parts and pricing page.

  1. Drill a 3/4" hole into the base material to the required depth (approximately 1-1/4" deep.)
  2. Blow the hole clean of dust and other material.
  3. Insert the anchor into the hole (Lead shield out).
  4. Position a setting tool or a 9/16" socket against the anchor outer cone. (The outer rim of the tool or socket should seat onto the lead shield rim.)
  5. Using the tool or socket, set the anchor by driving the lead sleeve over the cone using several sharphammer blows. (Be sure the anchor is at the required embedment depth.)
  6. Position the fixture, insert screw or bolt and tighten.

5. Cut and mount SDR 35 PVC drop pipe of diameter appropriate to Drop Bowl size and flow using RELINER adjustable stainless steel clamping brackets. Use a minimum of 2 brackets with a maximum spacing of 4 feet (RELINER clamping brackets will adjust to allow drop pipe to maintain correct stand off from wall).

6. Connection from Drop Bowl to drop pipe shall be by flexible external pipe connector. ("Fernco Recommended.)

7. Install appropriate pipe elbow to provide smooth transition into channel flow. We recommend a 45 degree elbow. 

Our Drop Bowl warranty is void if the drop pipe is not installed with the correct RELINER pipe support brackets as these brackets fully support the drop pipe and hold it off the wall the correct distance.  (see #5 above)

OPTIONAL STANDARD DROP BOWL INSTALLATION ANCHORS:  -- These parts are shipped assembled.

              3/8 X 1" X 16   18-8 stainless hex cap screw full thread,  3/8  18-8 stainless washers, 3/8  16 x 1-1/4 lead tamp-in expansion anchors        


RELINER® products are manufactured by Duran Inc. of East Haddam, CT and are sold nationally through local distributors and:

RELINER® / Duran Inc.
9 Matthews Drive, Unit A1/A2
East Haddam, CT 06423
Phone: (800) 508-6001, (860) 434-0277
Fax: (877) 434-3197

Price varies with complexity. Contact sales for quote or visit our web site at for suggested price list.


Contact sales at above numbers for copy of warranty.

Limitation of Liability
Duran Inc. liability is limited to the replacement or repair of defective parts, excluding cost of removal, installation or unauthorized repairs. Duran Inc. will not be responsible for incidental or consequential damages or for products which have been altered or modified. Information contained in this publication is based on field data and test results believed to be reliable. The product is intended for use by individuals having skill and expertise, at their own risk and discretion and in accordance with current industry practice.


Normal maintenance consists of routine inspection and flushing with a hose or pressure washer.


For technical consultation or additional information, and for custom design and fabrication services, please email: or call Phone (800) 508-6001 or (860) 434-0277, Fax (877) 434-3197