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The Oregon Administrative Rules contain OARs filed through July 15, 2014
 
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DEPARTMENT OF ENVIRONMENTAL QUALITY

 

DIVISION 73

CONSTRUCTION STANDARDS

 

340-073-0025

Tank Construction

The following construction and manufacturing requirements apply to all septic tanks, holding tanks, dosing tanks, multiple-compartment combination septic and dosing tanks, and dosing septic tanks manufactured for use in Oregon unless specifically exempted by OAR chapter 340, divisions 071 or 073.

(1) Compartments. Tanks may have single or multiple compartments.

(a) Single-compartment tanks and multiple-compartment tanks must meet or exceed the minimum volume requirements described in OAR chapter 340, divisions 071 and 073.

(b) Multiple-compartment tanks must comply with the following requirements:

(A) The liquid capacity of the first compartment must be at least 2/3 of the total required liquid capacity, as measured from the invert elevation of the first compartment's outlet Tee fitting;

(B) A compartment may not have an inside horizontal dimension of less than 24 inches.

(c) The liquid depth of any compartment must be at least 30 inches. Liquid depths greater than 72 inches may not be considered in determining the working liquid capacity unless the tank has a capacity greater than 3,000 gallons.

(2) Service access manhole. All tanks must have at least one service access manhole measuring at least 18 inches across its shortest dimension in each compartment.

(3) Watertightness. After installation, all tanks must be watertight. The installer must test each tank for watertightness by filling the tank to a point at least 2 inches above the point of riser connection to the top of the tank. During the test there may be no more than a one gallon leakage over a 24 hour period. The tank manufacturer must deliver watertight tanks and should test each tank for watertightness before the tank is shipped from the manufacturing plant.

(4) If the tank manufacturer does not fully assemble the tank, as with a two-piece concrete tank, the manufacturer must provide the bonding and sealing agents and an instruction manual for assembling the tank.

(5) Structure: All tanks must be able to support an earth load of at least 300 pounds per square foot when the maximum coverage does not exceed 3 feet. Tanks installed with more than 3 feet of cover must be reinforced to support the additional load. Lateral load must be 62.4 pcf of equivalent fluid pressure (EFP). Tanks must be able to withstand long-term external hydrostatic loads in addition to soil loads. Internal hydrostatic pressures must be omitted to allow for septage pumping during critical groundwater conditions. A 2,500 pound wheel load concentrated over the critical elements of the tank shall also be considered.

(6) Service access riser and cover. All tanks must be manufactured to accommodate installation of a watertight service access riser above one service access manhole. The riser must have a minimum nominal diameter of 20 inches when tank burial depths do not exceed 36 inches. Tanks designed for burial depths deeper than 36 inches must also be designed to accommodate installation of a 30-inch minimum diameter service access riser above each service access manhole. A gasketed riser cover must be provided and securely fastened or weighted to prevent unauthorized access.

(7) Inlet and outlet Tee fittings.

(a) The inlet and outlet Tee fittings must be of Schedule 40 P.V.C. plastic, Schedule 40 ABS plastic, or other equally durable materials approved by the department with a minimum diameter of 4 inches.

(b) The distance between the inlet and outlet Tee fittings in a single-compartment tank must at least equal the liquid depth of the tank.

(c) The inlet and outlet Tee fittings in a single compartment tank, where applicable, must be located at opposite ends of the tank. The inlet Tee fitting must be readily accessible by way of a watertight, 8-inch minimum diameter riser (with cover) and access hole positioned directly above the inlet Tee. The fittings must be attached in a watertight manner acceptable to the department.

(d) The inlet fitting in all single-compartment tanks, except dosing tanks, and in each compartment of multiple-compartment tanks, must be a "sanitary tee" extending at least 6 inches above and at least 12 inches below the normal high and low liquid levels, respectively.

(e) The outlet Tee fitting, holes, or ports provided in a vault or outlet effluent filter must be positioned to withdraw effluent horizontally from the clear zone at an elevation measured from the inside bottom of the tank to 65 to 75 percent of the lowest operating liquid depth. The net area of the ports must be at least 6 square inches. The outlet fitting in single-compartment tanks and in each compartment of multiple-compartment tanks must extend at least 6 inches above the highest normal liquid depth to provide scum storage. When the single-compartment tank is used as a holding tank, dosing septic tank, or dosing tank, the outlet Tee fitting must be provided with a watertight plug or omitted. The outlet Tee fitting may also be plugged or omitted in the last compartment of a multiple-compartment tank when a pump or siphon is placed in that last compartment.

(f) Ventilation must be provided through the fittings by means of a 2-inch minimum space between the top of the inlet Tee fittings and the adjacent tank surfaces.

(g) The invert of the inlet fitting must be at least 1 inch and preferably 3 inches above the invert of the outlet fitting or the highest normal liquid level.

(h) A convenient means of monitoring sludge and scum accumulation must be provided, with access extending to ground level.

(i) The tank manufacturer must provide with each Tee fitting an appropriate coupler that will provide a watertight connection between the fittings and the building and effluent sewer pipes.

(8) At least 10% of the inside volume of a tank must be above the highest normal liquid level to provide scum storage and reserve.

(9) Except as provided in OAR 340-073-0026, tanks shall be constructed of concrete, fiberglass, or other noncorrosive materials approved by the department:

(a) Precast concrete tanks must have a minimum wall, compartment, and bottom thickness of 2-1/2 inches and must be adequately reinforced. The top must be at least 4 inches thick.

(b) Cast-in-place tanks must be designed by a civil or structural engineer to the requirements of these rules, and the tank construction must be certified by the designer or qualified representative. A structural permit from the Building Codes Division or the municipality with jurisdiction (as defined in 455.010(4)) may be required when cast-in-place concrete tanks are used.

(c) Tanks made of other corrosion resistant materials must be constructed to provide structural integrity to meet the requirements of sections (3), (4), and (5) of this rule.

(10) All prefabricated tanks must be marked on the uppermost tank surface over the outlet with the liquid capacity of the tank, the burial depth limit, date of manufacture, and either the manufacturer's full business name or the number assigned by the department.

(11) Each commercial manufacturer of prefabricated tanks must provide two complete sets of plans and specifications, prepared by a registered professional engineer licensed to practice in Oregon, to the department for review and approval. Plans submittal must include the structural analysis, calculation of total gallons, operating gallons, gallons per inch, and buoyancy, including predetermined countermeasures.

(12) Each commercial manufacturer of pre-fabricated tanks must provide the department with written certification that tanks for use in onsite systems in the State of Oregon will comply with all requirements of this rule.

(13) An installation manual, on waterproof paper or placed within a weather-resistant container, must be provided by the manufacturer with each tank distributed. The manual must describe proper installation of the tank, riser(s) and lid, pipe connections, watertight testing procedures, backfill, and any special precautions or limitations.

[Publications: Publications referenced are available from the agency.]

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 5-1982, f. & ef. 3-9-82; DEQ 15-1986, f. & ef. 8-6-86; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0026

Septic Tanks

(1) Septic tanks must be constructed of concrete, fiberglass, steel, or other non-corrosive materials approved by the department.

(2) Steel septic tanks must be manufactured with 12-gauge or thicker steel. They must be coated inside and out with asphalt or other protective coatings that meet the American National Standards Institute UL 70 standard, Sections 25 through 43, or other coatings of equal or better performance approved by the department.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0030

Dosing Septic Tank

(1) A dosing septic tank may discharge effluent with a pump or dosing siphon from the clear zone at the outlet end of the tank. These may be considered for installations where the design flow does not exceed 600 gallons per day.

(2) Special Configuration:

(a) The minimum total primary volume of the tank must be 1,100 gallons for flows less than or equal to 450 gallons per day and 1,500 gallons for flows greater than 450 and up to 600 gallons per day.

(b) The submerged volume at the lowest operating liquid level must be at least 900 gallons. The remaining capacity must be used to ensure optimum surge capacity and reserve storage capacity.

(c) Liquid levels must be controlled in a manner that is consistent with pump dosing requirements described in OAR chapter 340, divisions 071 and 073.;

(d) All apparatus must be constructed and installed to facilitate ease of service without having to alter any other component.

(e) The installation manual described in OAR 340-073-0025(13) must include additional information about siphon selection, installation of the pump or siphon vault and screen, pump control and alarm levels, and the watertight pass-through methods for electrical wiring and pipe.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

Distribution Boxes, Drop Boxes, and Diversion Valves

340-073-0035

Distribution Boxes

(1) Distribution boxes must be constructed of concrete, fiberglass, or other materials acceptable to the department.

(2) Distribution boxes must be constructed of durable, watertight materials resistant to deterioration and be designed to accommodate watertight connections for the effluent sewer and header pipes. The top, walls, and bottom of concrete distribution boxes must be at least 1-1/2 inches thick. All distribution boxes must be able to support an earth load of at least 200 pounds per square foot.

(3) The invert elevation of all outlets must be the same and must be at least 2 inches below the inlet invert.

(4) Each distribution box must be provided with a sump extending at least 2 inches below the invert of the outlets unless otherwise authorized by the department.

(5) Distribution box covers must be marked with the manufacturer's full business name or number assigned by the department.

(6) Each manufacturer must provide the department with complete, detailed plans and specifications of the distribution box and must certify, in writing, that distribution boxes manufactured for use in onsite sewage systems in Oregon will comply with all requirements of this rule. Plans and specifications must be prepared under the supervision of and designed by a professional engineer licensed in accordance with ORS chapter 672.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 5-1982, f. & ef. 3-9-82; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0040

Drop Boxes

(1) Drop boxes must be constructed of concrete, fiberglass, or other materials acceptable to the department.

(2) Drop boxes must be constructed of durable, watertight materials resistant to deterioration and be designed to accommodate watertight connections for the effluent sewer and header pipes. The top, walls, and bottom of concrete drop boxes must be at least 1-1/2 inches thick. All drop boxes must be able to support an earth load of at least 200 pounds per square foot.

(3) The inverts of the inlet and overflow port must be at the same elevation. The invert of the header pipe port(s) leading to the absorption trench(es) must be 6 inches below the inlet invert.

(4) Drop box covers must be marked with the manufacturer's full business name or number assigned by the department.

(5) Each manufacturer must provide the department with complete, detailed plans and specifications of the drop box and must certify, in writing, that drop boxes manufactured for use in onsite systems in Oregon will comply with all requirements of this rule. Plans and specifications must be prepared under the supervision of and designed by a professional engineer licensed in accordance with ORS Chapter 672.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0041

Filter Fabric

Except as otherwise allowed by the department, filter fabric used as a barrier between the lower lens of drain media and the medium sand in a conventional sand filter system must meet the following specifications:

(1) Material synthetic fabric, either spunbonded or woven.

(2) Burst strength not less than 25 psi.

(3) Air permeability not less than 500 cfm per sq. ft.

(4) Water flow rate not less than 500 gpm per sq. ft. at 3 inches of head.

(5) Hydrophilic surface reaction to water.

(6) Equivalent opening size of 70 to 100 sieve.

(7) Chemical properties:

(a) Nonbiodegradable.

(b) Resistant to acids and alkalies within a pH range of 4 to 10.

(c) Resistant to common solvents.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 15-1986, f. & ef. 8-6-86; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0045

Diversion Valves

(1) Diversion valves must be constructed of material that is durable, corrosion-resistant, watertight, and designed to accommodate the inlet and outlet pipes in a secure and watertight manner.

(2) Diversion valves must be constructed with access to finished grade and large enough to provide for ease of operation and service of valve.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0050

Dosing Tanks

(1) Dosing tanks must meet the standards described in OAR 340-073-0025, except as otherwise allowed in this rule.

(2) Each dosing tank employing one or more pumps must have a minimum liquid capacity equal to the projected daily sewage flow for flows up to 1,200 gallons per day. The department will determine tank sizing for dosing tanks with projected daily sewage flows greater than 1,200 gallons per day. The liquid capacity of dosing tanks must be as measured from the invert elevation of the inlet fitting.

(3) Each dosing tank must be provided with a service access manhole having a minimum horizontal measurement of 18 inches.

(4) Each dosing tank proposed to serve a commercial facility containing more than one pump or siphon must be provided with at least one service access manhole that provides adequate space to construct, install, service, and operate the equipment in accordance with the requirements of OAR chapter 340, divisions 071 and 073.

(5) The installation manual described in OAR 340-073-0025(13) must include additional information about siphon selection, installation of the pump or siphon screen, pump control and alarm levels, and the watertight pass-through methods for electric wiring and pipe.

(6) Dosing tanks with siphons must be designed and sized for each specific project. The tank manufacturer must specify the type or model of siphon, screen, and related apparatus that are compatible with each dosing tank.

(7) The inlet fitting must extend below the lowest operating level of the pump or siphon.

[Publications: Publications referenced are available from the agency.]

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 5-1982, f. & ef. 3-9-82; DEQ 15-1986, f. & ef. 8-6-86; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0055

Dosing Assemblies: Effluent Pumps, Controls and Alarms, and Dosing Siphons

(1) Design and equipment must emphasize ease of maintenance, longevity, and reliability of components and must be proven suitable by operational experience, test, or analysis acceptable to the department.

(2) Easy means of electrical and plumbing disconnect must be provided. All apparatus must be constructed and installed to facilitate ease of service without having to alter any other component.

(3) Component materials must be durable and corrosion-resistant such as Type 316 stainless steel, suitable plastics, or 85-5-5-5 bronze.

(4) Pumps, Siphons, Controls, and Alarms. All pumps, siphons, controls and related apparatus must be field tested under working conditions and found to operate and perform satisfactorily. Electrical components used in onsite systems must comply with applicable requirements of the State of Oregon Electrical Code and the standards in this section.

(a) Motors must be continuous-duty with overload protection.

(b) Pumps must have durable impellers of bronze, cast iron, or other materials approved by the department.

(c) Submersible pumps must be provided with an easy, readily accessible means of electrical and plumbing disconnect and a noncorrosive lifting device as a means of removal for servicing.

(d) Except where specifically authorized in writing by the agent, the pump or siphon must be placed within a corrosion-resistant screen or vault with a filtering device that extends into or above the tank's service access manhole. The screen or filtering device must have at least 12 square feet of surface area, with 1/8-inch openings. In lieu of the screen, the agent may allow other methods with equal or better performance in preventing the passage of suspended solids to the pump or siphon.

(e) Pumps must be automatically controlled by float switches with a minimum rating of 12 amps at 115 volts A.C. or by a department-approved, equally reliable switching mechanism. Except as otherwise required in this division, the switches must be installed so that no more than 20% of the projected daily sewage flow is discharged each cycle. The pump "off" level must be set to maintain the liquid level above the top of the pump or to the designer and pump manufacturer's specifications.

(f) An audible and visual high water level alarm with manual silence switch must be located in or near the building served by the pump. Only the audible alarm may be user-cancelable. The switching mechanism within a dosing tank or chamber controlling the high water level alarm must be located so that at time of activation the tank has a remaining volume equal to 1/3 or more of the system's design flow, as measured below the invert of the inlet, for effluent storage. The alarm and pump must be on separate circuits. Commercial applications using duplex pumps are not subject to the 1/3 storage reserve requirement.

(g) When a system has more than one pump, the department may require the pumps to be wired into the electrical control panel to function alternately after each pumping cycle. If either pump should fail, the other pump will continue to function while the high water level alarm activates. A cycle counter must be installed in the electrical control panel for each pump.

(h) All pump installations must be designed with adequate sludge storage volume below the effluent intake level of the pump.

(i) All commercial systems with a design flow greater than 600 gallons must be constructed in duplex (two or more alternating pumps) unless otherwise authorized in writing by the department. Controls must be provided such that an alarm will signal when one1 of the pumps malfunctions.

(j) All pumps serving commercial systems must be operated through a pre-manufactured electrical control panel. A means of monitoring pump performance through the use of elapsed-time meters and cycle counters is required.

(k) Where multiple pumps are operated in series, an electrical control panel must be installed to prevent the operation of a pump or pumps preceding a station that experiences a high level alarm event.

(5) Dosing Siphons. Dosing siphons used in onsite systems must comply with the following minimum requirements.

(a) The siphon must be constructed of corrosion-resistant materials.

(b) The siphon must be installed within a compatible tank in accordance with the siphon manufacturer's recommendations.

(c) The siphon manufacturer must provide installation and maintenance instructions to the owner.

(d) The installation must include a device that tracks the operation of the siphon by measuring cycle events and records them by means of an event counter mounted within the dwelling or structure served.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 23-1981(Temp), f. & ef. 9-2-81; DEQ 5-1982, f. & ef. 3-9-82; DEQ 15-1986, f. & ef. 8-6-86; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 12-1997, f. & cert. ef. 6-19-97; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0056

Effluent Filters

Effluent filters used in onsite systems must meet the following criteria.

(1) Filters must be of durable, resilient, corrosion resistant, non-degradable materials resistant to deformation under normal operating conditions.

(2) Filters must be designed to prevent the escape of sludge or scum during normal operation and in the event of a malfunction, including filter clogging.

(3) The filter must retain all particles greater than 1/8 inch.

(4) The filter assembly must baffle the sludge and scum layers to prevent the escape of gross solids during sludge bulking or gas ebullition.

(5) Filters must be designed and positioned to allow for easy, trouble-free removal from and reinstallation to the screen apparatus from the assembly.

(6) The assembly must be capable of withstanding stresses placed upon it by installation, operation, and service.

(7) The assembly in the septic tank must perform as a conventional tank outlet that meets the requirements of OAR 340-073-0025(6) when the filter is removed.

(8) The filter must be designed to handle the flow of the system it is to serve without excessive maintenance. For a single family dwelling, maintenance is considered "excessive" when the filter requires service or cleaning more than one time per year. Service must be performed each time the tank is pumped and in accordance with the manufacturer's specifications.

(9) To obtain department approval, the manufacturer of an effluent filter must provide the department with the necessary technical data to show that the design and materials comply with this rule. The manufacturer must provide an operation and maintenance manual with each unit distributed.

(10) Effluent filter units external to the tank must be watertight.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0060

Pipe Materials and Construction

(1) Effluent Sewer Pipe: The effluent sewer must be constructed with materials in conformance with state building sewer standards. The effluent sewer pipe must have a minimum diameter of 3 inches. When the septic tank is fitted with an effluent filter, the minimum nominal diameter of piping may be reduced to 1-1/4 inches.

(2) Underdrain pipe. Underdrain pipe must meet or exceed the requirements for Class 125 PVC pressure pipe as identified in ASTM Specification D 2241. The pipe and fittings must be marked as required by ASTM Specification D 2241. The underdrain pipe must be perforated in accordance with subsection (4)(d) of this rule or with 1/4-inch slots cut halfway through the pipe at 4 inches center to center.

(3) Polyvinyl chloride (PVC) pressure transport pipe, pressure manifolds, and pressure lateral pipe and fittings must meet or exceed the current requirements for Class 160 PVC 1120 pressure pipe as identified in ASTM Specification D 2241. The pipe and fittings must be marked as required by ASTM Specification D 2241. For pipe diameters of 1 inch or less, the minimum pressure rating is 200 pounds per square inch (psi). For pipe diameters greater than 1 inch, the minimum pressure rating is 160 psi.

(4) Distribution and Header Pipe and Fittings.

(a) Polyethylene distribution pipe in 10 foot lengths and header pipe in lengths of 10 feet or greater must meet the current ASTM Specification F 405. Pipe and fittings must also pass a deflection test withstanding 350 pounds per foot without cracking or collapsing using the method in ASTM 2412. Pipe used in absorption facilities must be heavy duty. Markings must meet requirements in ASTM F 405.

(b) Polyvinyl chloride (PVC) distribution and header pipe and fittings must meet the most current ASTM Specification D 2729. Pipe and fittings must pass a deflection test withstanding 350 pounds per foot without cracking or collapsing using the method found in ASTM 2412. Markings must meet requirements in ASTM Specification D 2729.

(c) Polyethylene smooth wall distribution and header pipe in 10-foot length and fittings must meet the most current ASTM Specification F 810. Pipe and fittings must also pass a deflection test of 350 pounds per foot without cracking or collapsing by using the method found in ASTM 2412. Markings shall meet the requirements in ASTM Specification F 810Section 9.

(d) The three types of plastic pipe described above must have two rows of holes spaced 120 degrees apart and 60 degrees on either side of a center line. For distribution pipe, a line of contrasting color must be provided on the outside of the pipe along the line furthest away and parallel to the two rows of perforations. Durable ink markings must cover at least 50% of the pipe. Markings may consist of a solid line, letters, or a combination of the two. Intervals between markings must not exceed 12 inches. The holes of each row may not be more than 5 inches on center and must have a minimum diameter of 1/2 inch.

[Publications: Publications referenced are available from the agency.]

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 5-1982, f. & ef. 3-9-82; DEQ 9-1982, f. & ef. 6-16-82; DEQ 15-1986, f. & ef. 8-6-86; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

Nonwater-Carried Waste Disposal Facilities, Materials, and Construction

340-073-0065

Privies and Portable Toilet Shelters

(1) Privies and portable toilet shelters must comply with the following general requirements.

(a) Structures must be free of hostile surface features, such as exposed nail points, sharp edges, and rough or broken boards, and must provide privacy and protection from the elements.

(b) Building ventilation must be equally divided between the bottom and top halves of the room and must be adequate to allow for the free escape of gases and odors. All vents must be screened with 16 mesh screen of durable material.

(c) Buildings must be of fly-tight construction and must have self-closing doors with an inside latch.

(d) Pits, tanks, or vaults must be vented to the outside atmosphere by a flue or vent stack having a minimum inside diameter of 4 inches. Vents must extend at least 12 inches above the roof.

(e) Interior floors, walls, ceilings, partitions, and doors must be finished with readily cleanable, impervious materials resistant to wastes, cleansers, and chemicals. Floors and risers must be constructed of impervious material and prevent entry of vermin.

(2) Portable Toilet Shelters. Portable toilet shelters may be prefabricated, skid mounted, or mobile. In addition to the requirements in section (1) of this rule, portable toilet shelters must:

(a) Provide at least 1 square foot of screened ventilation to the outside atmosphere for each seat;

(b) Provide at least 9 square feet of floor space for each seat;

(c) Be furnished with a toilet tissue holder for each seat;

(d) Be located in areas readily accessible to users and to pumping and cleaning services; and

(e) Provide separate compartments with doors and partitions or walls of sufficient height to insure privacy in multiple-unit shelters except that separate compartments are not required for urinals.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 & 454.775 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0070

Unsealed Earth Pits for Privies

(1) The pit must be constructed with material and in a manner to prevent rapid deterioration, provide adequate capacity, and facilitate maintenance under ordinary use.

(2) Unless otherwise approved by the agent, the pit must provide a capacity of 50 cubic feet for each seat installed in the privy building and must be at least 5 feet deep. The area within 16 inches of the surface grade may not be counted as part of the 50 cubic-foot capacity.

(3) Pit cribbing must fit firmly and be in uniform contact with the earth walls on all sides and must rise at least 6 inches above the original ground line and descend to the full depth of the pit. Pit cribbing below the soil line may be omitted in rock formations.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 & 454.775 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0075

Self-Contained Nonwater-Carried Toilet Facilities

(1) General Standards. All self-contained, nonwater-carried toilet facilities must comply with the following requirements.

(a) They must have water-tight chambers constructed of reinforced concrete, plastic, fiberglass, metal, or other material of acceptable durability and corrosion resistance, approved by the department, and designed to facilitate the removal of the wastes.

(b) Black wastes must be stored in an appropriate chamber until removal for final treatment elsewhere. Wastes must be removed from the chamber whenever necessary to prevent overflow.

(c) Chemicals containing heavy metals such as copper, cadmium, and zinc, must not be used in self-contained toilet facilities.

(d) All surfaces subject to soiling must be impervious, easily cleanable, and readily accessible.

(2) Vault Toilet Facilities.

(a) The capacity of vaults must be at least 350 gallons or, in places of employment, 100 gallons per seat.

(b) Caustic must be added routinely to vault chambers to control odors.

(3) Chemical Toilet Facilities.

(a) Toilet bowls must be constructed of stainless steel, plastic, fiberglass, ceramic, or other material approved by the department.

(b) Waste passages must have smooth surfaces and be free of obstructions, recesses, or cross braces that would restrict or interfere with flow of black wastes.

(c) Biocides and oxidants must be added to waste detention chambers at rates and intervals recommended by the chemical manufacturer and approved by the department.

(d) Chambers and receptacles must provide a minimum storage capacity of 50 gallons per seat.

(e) Portable shelters housing chemical toilets must display the business name of the licensed sewage disposal service that is responsible for servicing them.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 & 454.775 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 9-1984, f. & ef. 5-29-84; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0080

Construction of Gray Water Waste Disposal Sumps

A gray water waste disposal sump must consist of a receiving chamber, settling chamber, and either a seepage chamber or absorption trench.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.610, 454.615 & 454.775 
Hist.: DEQ 10-1981, f. & ef. 3-20-81; DEQ 8-1983, f. & ef. 5-25-83; DEQ 16-1986, f. & ef. 9-16-86; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

340-073-0085

Flexible Membrane Liners for Sand Filters Treating Septic Tank Effluent

(1) Unsupported polyvinyl chloride (PVC) must have the following properties (Property -- Test Method).

(a) Thickness -- ASTM D1593, Para 9.1.3, 30 mil, minimum

(b) Specific Gravity (minimum) -- ASTM D792, Method A

(c) Minimum Tensile Properties (each direction) -- ASTM D882

(A) Breaking Factor (pounds/inch width) -- Method A or B (1 inch wide), 69

(B) Elongation at Break (percent) -- Method A or B, 300

(C) Modulus (force) at 100% Elongation (pounds/inch width) -- Method A or B, 27

(d) Tear Resistance (pounds, minimum) -- ASTM D1004, Die C, 8

(e) Low Temperature -- ASTM D1790, -20° F

(f) Dimensional Stability (each direction, percent change maximum) -- ASTM D1204, 212° F;, 15 min., ±5

(g) Water Extraction -- ASTM D1239, 0.35% max

(h) Volatile Loss -- ASTM D1203,Method A, 0.7% max

(i) Resistance to Soil Burial (percent change maximum in original value) -- ASTM D3083:

(A) Breaking Factor, -5

(B) Elongation at Break, -20

(C) Modulus at 100% Elongation, ±10.

(j) Bonded Seam Strength (factory seam, breaking factor, ppi width) -- ASTM D3083, 55.2

(k) Hydrostatic Resistance -- ASTM D751, Method A, 82.

(2) Installation Standards.

(a) Patches, repairs, and seams must have the same physical properties as the parent material.

(b) Site considerations and preparation.

(A) The supporting surface slopes and foundation to accept the liner must be stable and structurally sound with appropriate compaction. Particular attention must be paid to the potential of sink hole development and differential settlement.

(B) Soil stabilizers such as cementations or chemical binding agents may not adversely affect the membrane; cementations and chemical binding agents may be potentially abrasive agents.

(c) Only fully buried membrane liner installation may be considered to avoid weathering.

(d) Unreinforced liners have high elongation and can conform to irregular surfaces and follow settlements within limits. Unreasonable strain reduces effective thickness and may reduce life expectancy by lessening the chemical resistance of the thinner (stretched) material. Every effort must be made to minimize the strain (or elongation) anywhere in the flexible membrane liner.

(e) Construction and installation.

(A) Surface condition.

(i) Preparation of earth subgrade. The prepared subgrade must be of soil types no larger than Unified Soil Classification System (USCS sand (SP) to a minimum of 4 inches below the surface and free from loose earth, rock, fractured stone, debris, cobbles, rubbish and roots. The surface of the completed subgrade must be properly compacted, smooth, uniform, and free from sudden changes in grade. Importing suitable soil may be required.

(ii) Maintenance of subgrade. The earth subgrade must be maintained in a smooth, uniform, and compacted condition during installation of the lining.

(B) Climatic conditions.

(i) Temperature. Placing liner outside the desirable temperature range must be avoided. The desirable temperature range for membrane installation is 42° F. to 78° F. Lower or higher temperatures may have an adverse effect on transportation, storage, field handling, and placement, seaming, and backfilling; and attaching boots and patches may be difficult.

(ii) Wind. Placing the liner in high wind must be avoided. Wind may have an adverse effect on liner installation such as interfering with liner placement. Mechanical damage may result. Cleanliness of areas for boot connection and patching may not be possible. Alignment of seams and cleanliness may not be possible.

(iii) Precipitation. Seaming, patching, and attaching "boots" must be done under dry conditions. When field seaming is adversely affected by moisture, portable protective structures and other methods must be used to maintain a dry sealing surface. Proper surface preparation for bonding boots and patches may not be possible.

(C) Structures. Where penetrations are necessary, liners must be attached to pipes with a mechanical type seal supplemented by a chemically compatible caulking or adhesives to effect a liquid-tight seal. Maximum compaction must be provided in the area adjacent to pipes to compensate for any settlement.

(D) Liner Placement.

(i) Size. The final cut size of the liner must be carefully determined and ordered to generously fit the container geometry without field seaming or excess straining of the liner material.

(ii) Transportation, handling, and storage. Transportation, handling, and storage procedures must be planned to prevent material damage. Material must be stored in a secured area and protected from adverse weather.

(iii) Site inspection. A site inspection must be carried out by the agent and the installer before liner installation to verify surface conditions and other conditions important to installation.

(iv) Deployment. Panels must be positioned to minimize handling. Seaming should not be necessary. Bridging or stressed conditions must be avoided with proper slack allowances for shrinkage. The liner must be secured to prevent movement and promptly backfilled.

(v) Anchoring trenches. The liner edges must be secured frequently in a backfilled trench.

(vi) Field seaming. Field seaming, if absolutely necessary, must be attempted only when weather conditions are favorable. The contact surfaces of the materials must be clean of dirt, dust, moisture, or other foreign materials. The contact surfaces must be aligned with sufficient overlap and bonded in accordance with the suppliers recommended procedures. Wrinkles must be smoothed out and seams must be inspected by nondestructive testing techniques to verify their integrity. As seaming occurs during installation, the field seams must be inspected continuously, and any faulty area repaired immediately.

(vii) Field repairs. Traffic on the lined area must be minimized. Any necessary repairs to the liner must be patched using the same lining material and following the recommended procedure of the supplier.

(viii) Final inspection and acceptance. Completed liner installations must be visually checked for punctures, rips, tears, and seam discontinuities before placement of any backfill. At this time the installer must also manually check all factory and field seams with an appropriate tool. In lieu of or in addition to manual checking seams, either of the following tests may be performed:

(I) Wet Test. The lined basin must be flooded with water to the 1-foot level after inlets and outlets have been plugged. There may not be any loss of water in a 24 hour test period.

(II) Air Lance Test. All bonded seams must be checked using a minimum 50 PSI (gauge) air supply directed through a 3/16 inch (typical) nozzle held not more than 2 inches from the seam edge and directed at the seam edge. Riffles indicate unbonded areas within the seam or other undesirable seam construction.

Stat. Auth.: ORS 454.625 & 468.020 
Stats. Implemented: ORS 454.615 & 454.780 
Hist.: DEQ 5-1982, f. & ef. 3-9-82; DEQ 15-1986, f. & ef. 8-6-86; DEQ 27-1994, f. 11-15-94, cert. ef. 4-1-95; DEQ 11-2004, f. 12-22-04, cert. ef. 3-1-05

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