Comparisons
Chemical Equipment Selection Tables
Tank materials, elastomers, pump types and isolation valves in one place. Each cell is taken from a LibertyCES guide and links back to it.
How to read these
These tables compile what our guides already state, with no new claims. A dash means the guides do not state that point, not that it is unknown. Selection depends on chemistry, concentration and temperature, so confirm any choice against the linked guide and the manufacturer before ordering.
Storage tank materials
Material properties as stated on LibertyCES guide pages; blank cells are not stated by the guides.
| Option | Construction | Temperature limit | Typical service life or failure mode | Chemistry notes | When the guides recommend it |
|---|---|---|---|---|---|
| HDPE | Linear polyethylene; chains held by van der Waals forces only, with no covalent bonds between chains. Source | Recommended limit is around 120°F; beyond that the guide points to polypropylene (180–200°F) or FRP. Source | Stress cracking symptoms typically appear within 12–36 months in trade-grade hypochlorite service. Source | HDLPE covers roughly 95% of industrial and municipal chemicals when correctly specified for resin, wall thickness, and temperature. Source | One manufacturer's technical bulletin recommends HDLPE, not XLPE, for sodium hypochlorite; the guide notes manufacturers disagree. Source |
| XLPE | Covalent bonds between chains (crosslinking), described as the strongest bond type and resistant to disruption by oxidizers. Source | Rated performance to ~140°F; ASTM D1998 rates Type I cross-linkable polyethylene tanks for continuous service below 150°F. Source | Typical service life in NaOCl service is 20+ years, against 12–36 months for standard HDPE. Source | One manufacturer's guidance states XLPE fails within six months of service at 98% sulfuric acid. Source | The guide's specifier uses XLPE exclusively for oxidizing chemical applications; HDPE is unapproved on any hypochlorite specification. Source |
| FRP | Filament-wound construction to ASTM D3299, specifying the resin system and corrosion barrier needed to resist chemical attack and wicking. Source | — | 20+ years when well-specified; blistering or weeping comes from wrong resin/liner selection and inconsistent lay-up. Source | A resin-rich interior layer (C-Veil or synthetic veil) matched to the MSDS and temperature forms the chemical-resistant barrier protecting the structural fiberglass. Source | Considered when HDPE's recommended limit of around 120°F is exceeded. Source |
| Polypropylene | Extrusion-wound, with solid walls up to 3.5 inches thick. Source | Continuous service up to 200°F for water and 180°F for aggressive chemicals. Source | 20–30+ year life; field-weldable and repairable. Source | Chemical immunity across the full pH spectrum (0–14). Source | Right choice when heat or aggressive chemistry pushes HDPE and XLPE past their limits. Source |
Elastomers and seal materials
Seal and elastomer properties as stated on LibertyCES guide pages; confirm against the actual chemical, concentration, and temperature.
| Option | What it is | Resists | Listed weaknesses | Notes from the guides |
|---|---|---|---|---|
| Buna-N | Same as NBR: nitrile rubber for oil, fuel, grease, and hydraulic-fluid applications. Source | Petroleum oils, fuels, greases, hydraulic fluids. Source | Listed weaknesses: ozone, weathering, steam, many ketones, esters, chlorinated solvents. Source | Parts: O-rings, seals, gaskets. Use: cost-effective oil and fuel sealing. Source |
| EPDM | An ethylene propylene diene monomer elastomer with excellent resistance to ozone, weathering, and steam. Source | Water, steam, caustic, ozone, weathering, many aqueous chemicals. Source | Listed weaknesses: oils, fuels, hydrocarbons, many solvents. Source | In continuous-duty sodium hypochlorite service above 10 percent available chlorine, EPDM is not an appropriate specification. Source |
| FKM (Viton) | A fluorocarbon elastomer with a fluorine-carbon backbone, commercially known as Viton, chemically inert to most oxidizing environments. Source | Oils, fuels, high heat, many solvents, many aggressive chemicals. Source | Listed weaknesses: steam, hot water, strong bases, amines, ketones. Source | In sodium hypochlorite service it maintains its rated cross-sectional geometry at concentrations up to 15 percent within its rated temperature range. Source |
| PTFE | A fluoropolymer barrier, not an elastomer. Source | Broad chemical resistance, aggressive acids, oxidizers, high-purity service. Source | Listed weaknesses: creep, cold flow, permeation in certain media, low elasticity. Source | Usually acts as the chemical barrier while another material behind it provides flexibility, compression, and mechanical support. Source |
Chemical pump types
Each cell is sourced to a LibertyCES page; blank cells mean the pages do not state it.
| Option | How it works | Strengths | Limits and failure modes | When the guides recommend it |
|---|---|---|---|---|
| AODD | Reciprocating diaphragms move fluid; compressed air cycles the diaphragms. Source | Simple at the point of use, tolerates harsh service, self-primes, can run dry and stalls safely. Source | Every stroke exhausts air; mufflers cut noise but add a restriction and service item. Source | Keep AODD in consideration when a reliable air network exists, electrical power is impractical, or the needed hazardous-location approval is unavailable in electric. Source |
| EODD | Electric drive cycles the diaphragms; QUANTM uses a compact gearbox-free transverse-flux motor. Source | Graco states up to 80% lower energy usage and cost vs. pneumatic pumps; actual savings depend on hours, air cost, leaks, load and electric rate. Source | Hazardous-location approvals vary by exact voltage, motor and configuration; one model's approval must not be generalized to the family. Source | Evaluate switching when run hours make air cost matter, air pressure at the pump is inconsistent, noise or icing is a problem, or PLC/SCADA control is needed. Source |
| Mag-drive | Sealless: an external motor magnet couples through a sealed housing to an internal impeller magnet. Source | No mechanical seal to leak, eliminating the single largest failure point in a sealed pump. Source | Trades the seal failure for dry running, cavitation and magnet decoupling, several of which can fail silently without a leak. Source | Use when leak elimination is the priority, protection instrumentation will be added, and temperature/pressure stay within the model's rated ceiling. Source |
| Mechanically sealed | — | Generally more forgiving of brief dry-run conditions, though not indefinitely. Source | Real, ongoing leak risk at the seal face over the pump's service life, especially in aggressive chemical service. Source | Use when dry-run tolerance matters more than leak elimination, or operating conditions exceed mag-drive temperature/pressure ceilings. Source |
| Peristaltic metering | Self-priming tube pump: a rotating roller assembly compresses a flexible tube to meter chemical into the process line. Source | Passes gas slugs from off-gassing chemicals such as sodium hypochlorite and peracetic acid without the vapor lock that can affect diaphragm pumps. Source | Tubing life, pressure, flow range and maintenance frequency must fit the service. Source | Suited to gaseous chemicals, shear-sensitive fluids, viscous slurries and solids, and low-moisture fluids. Source |
| Diaphragm metering | — | Widely used when higher discharge pressure and check-valve metering are required. Source | Gas accumulating in the liquid head compresses rather than discharging, causing sharp chemical delivery drops while the pump sounds normal. Source | A diaphragm pump can still be specified correctly for off-gassing chemicals if the material and mechanism tradeoffs are disclosed. Source |
| Pneumatic bellows | Moves fluid by cycling a check valve on every stroke, so each cycle is a discrete pressure event. Source | — | Repeated shear at the valve seat destabilizes the slurry suspension, encouraging particle agglomeration. Source | — |
Isolation valve types
Each cell is sourced to a LibertyCES page; blank cells mean the pages do not state it.
| Option | How it seals | Best fit | Limits | Source notes |
|---|---|---|---|---|
| Knife gate | A flat gate travels perpendicular to flow; its bevel-edged bottom cuts through settled solids. Source | Full-bore on/off isolation in heavy slurry, tailings and mining-slurry lines where solids can pack in the seat. Source | Not a throttling valve; designed for fully open or fully closed service, not intermediate positions. Source | AVCO 6100 Series: seat mechanically locked into the body via a stainless retainer ring; meets MSS-SP-81 and TAPPI TIS 405-8. Source |
| Ball | Rotating ball with a bore; quarter-turn with tight shutoff. Source | Clean or lightly-loaded process lines, and severe, chlorine or cryogenic service. Source | Standard ball/seat geometry is not purpose-built for heavy solids; abrasive slurry can score the ball and seat over repeated cycling. Source | AVCO ball valve families (1100/HP1100/1500/9100 Series) are fire-safe, up to 6000 WOG. Source |
| Butterfly | Rotating disc on a shaft, quarter-turn, with compact face-to-face length. Source | Large-diameter isolation where space and weight matter. Source | Disc and shaft sit in the flow path; in heavy slurry abrasive solids can erode the seat and disc edge faster than in clean service. Source | AVCO BFV HP high-performance butterfly, up to 60" Class 150. Source |
| Plug / sleeved plug | Soft-seated sleeved plug valve with a fourth sealing barrier and zero packing adjustments during thermal cycling. Source | Severe service and slurry survival; cavity control and low-leak emissions, with correct liner/sleeve selection essential. Source | The XOMOX HF4D is 1/2 to 12 inches, Class 300, -20°F to 500°F. Source | Crane CPE HF4D lists ISO 15848-1 and API 641, with zero packing adjustments during thermal cycling. Source |
| True union ball | Double O-ring stem seals with reversible PTFE seats as standard, FPM seals. Source | True-union quarter-turn valves for clean on/off service. Source | Hayward TBH is rated 250 PSI / 16 Bar (socket/threaded) or 150 PSI / 10 Bar (flanged) at 70°F, non-shock. Source | Ball, seats and seals can be serviced or replaced without cutting the line or disturbing adjacent piping. Source |
| Diaphragm | Weir-style diaphragm design, with PTFE or composite diaphragm options for off-gassing service. Source | Used when service is more demanding than clean on/off isolation: corrosive chemicals, slurries, suspended solids and abrasive media. Source | — | Asahi Type-14 diaphragm valve is positioned for aggressive off-gassing chemicals plus suspended solids. Source |
Related
Reviewed by James Riggins, 30+ years specifying water and chemical process equipment · Updated