Standards · September 10, 2024

Five heat-treatment myths that hold up shipments

ISPM-15 is a short, clear standard that almost everybody misremembers in the same five ways. Each one of these has stopped a container somewhere.

Published: September 10, 2024
Reading time: 8 minutes
Written by: Yard desk
Sections: 7 passages

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8 min: Reading time
7: Passages
Standards: Category
September 10: Published
94%: Intake reused
11.6 kg: CO₂e per reuse

Heat treatment is not complicated: 56 °C at the core of the wood for thirty continuous minutes, marked with the IPPC stamp and the facility registration. Almost every delayed consignment we hear about comes from one of these five misunderstandings.

Myth one: export pallets must be new

Nothing in ISPM-15 refers to the age of the wood. A recycled deck that is structurally sound, bark-free and correctly treated is fully compliant. We re-treat and re-stamp recycled pallets in our own chamber precisely because this myth costs exporters a great deal of money for no phytosanitary benefit.

Myth two: kiln-dried means heat-treated

KD describes moisture content; HT describes a thermal process with a specific time-and-temperature profile and a mark to evidence it. A kiln-dried pallet without the stamp is not compliant, and plenty of kiln schedules never reach 56 °C at core.

Myth three: a mark lasts forever

The mark certifies the wood as it was when treated. Repair the pallet with an untreated board and the unit is no longer compliant, even though the stamp is still there and still legible. This is the single most common cause of a border hold: a correctly marked pallet with one innocent replacement board.

Myth four: bark is cosmetic

Bark on any component — including a corner block — fails inspection regardless of treatment, because bark is where the pests live. Australia and New Zealand inspect for this specifically and are entirely unsentimental about it.

Myth five: dunnage does not count

Bracing, blocking, chocks and loose dunnage inside the container are all wood packaging material and all in scope. We have seen a compliant pallet load held because somebody cut a length of untreated two-by-four to stop a drum rolling.

Marks on two opposite sides, legible and unpainted.
No bark anywhere, blocks included.
No post-treatment repairs with unmarked wood.
Treatment code accepted at the destination — methyl bromide is refused in most markets.
All dunnage and bracing treated and marked too.

If you are unsure

Send us photographs of the stamp and the stringer. We read these every week and can usually tell you in an hour whether your existing stock will travel or needs re-treating. It is a cheaper conversation than a held container.

Written at the Meeks Blvd yard, St. Louis, and published on September 10, 2024. Markets and specifications move; if a figure here no longer matches what you are seeing, tell us and we will update it. Our model constants live on the Carbon Ledger.

How this was written

Drafted at the grading line from our own weighbridge records, line notes and customer correspondence. Figures quoted as ours are measured; figures quoted from the wider industry are labelled as estimates. Nothing here was written to rank for a search term, and we correct articles rather than quietly deleting them.

Author: Yard desk
Published: September 10, 2024
Category: Standards
Reviewed: Annually, with the model constants
Corrections to: sales@repalletshop.com

What to do with this

Check the figures against your own invoices before acting on them.
Ask us for the underlying scale tickets if you need audit evidence.
Send the article to whoever owns your pallet spec — most of this is their decision.
Disagree in writing. Several of these pieces exist because a customer corrected us.

How to cite

Yard desk, “Five heat-treatment myths that hold up shipments”, Repallet Shop, September 10, 2024. repalletshop.com/blog/heat-treatment-myths

Three more on the same shelf

Yard reference

Every number we publish, in one place

The same appendix appears at the foot of our reference pages so you never have to leave an article to check a figure. All of it is revised annually and matches the constants used by the Carbon Ledger.

Stock specification

Stock footprint: 48" × 40" (1219 × 1016 mm)
Deck height, GMA stringer: 5½" (140 mm)
Deck height, block pallet: 5¾" (146 mm)
Deck height, EPAL 1: 144 mm
Board thickness, nominal: ⅝" (16 mm)
Top deck boards, #1 grade: 6–7
Bottom deck boards, #1 grade: 4–5
Stringers per pallet: 3, notched or solid
Species: Mixed hardwood, oak-dominant
Mass, recycled 48×40: 33–42 lb / 15–19 kg
Mass, new 48×40: 37–48 lb / 17–22 kg
Mass, EPAL 1: 22–25 kg / 49–55 lb
Moisture ceiling at dispatch: ≤ 19%
Fasteners: Helical-thread 2½"

Typical values for our 48×40 recycled stock. Exact board counts vary by grade and batch.

Order terms

Metro delivery minimum: 100 pallets
Pickup minimum (selling to us): 50 pallets
Drop-off minimum: None, during yard hours
Out-of-region freight: Full trailer
Quote validity: 14 days
Standing-order pricing: Fixed for the quarter
First order terms: Prepaid or card
Account terms: Net 30, approved
Buy-back payment: Cheque or ACH, 10 business days
Sample before contract: 20 pallets, free
Grade dispute remedy: Same-day re-grade, replace or credit
Reserved stock: Up to 8 weeks against a confirmed order

Standing-order customers get fixed quarterly pricing.

The yard, in facts

Address: 9869 Meeks Blvd, St. Louis, MO 63132
Founded: 2009
Zero landfill since: March 2017
Grading lanes: Four, plus new and heat-treated
Named defects on the wall: Thirteen
Covered storage: Two roofed bays
Dock doors: Four at 48 in, plus drive-on
Weighbridge: On site, certified
Trailers owned: Nine, plus two flatbeds
Trailer staging spaces: Twelve
Pallets handled last year: 412,000
Hardwood kept in circulation: 4,780 tons
Decks repaired weekly: ≈ 3,000
Intake leaving as pallets: 94%
Mean further lives per deck: 4.7

Counted at the weighbridge and the grading line.

Grades, side by side

Load figures are observed operating capacities for a 48×40 footprint under a uniformly distributed load. Apply your own safety factor — 1.5 for dynamic handling, 2.0 for long-term racked storage. Price index: 100 = new hardwood.
Grade	Top / bottom boards	Repairs allowed	Static	Dynamic	Racked	Price index
A / Premium	7 / 5	None visible	4,600 lb	2,800 lb	1,800 lb	42–52
#1 Grade	6–7 / 4–5	Full-length companions	4,000 lb	2,500 lb	1,500 lb	30–40
#2 Grade	5–6 / 3–4	Plugs and companions	3,200 lb	1,800 lb	Not advised	20–28
Core / Mixed	As arrived	Unsorted	Unrated	Unrated	No	12–20
New hardwood	7 / 5	n/a	5,000+ lb	3,000 lb	2,200 lb	100
Heat-treated #1	6–7 / 4–5	Companions, re-treated	4,000 lb	2,500 lb	1,500 lb	38–48

Footprints we stock or build

48×40 is roughly 72% of our intake. Odd sizes arrive as they arrive — ask before planning around them.
Footprint	Metric	Known as	Typical use
48" × 40"	1219 × 1016 mm	GMA / grocery standard	General distribution, grocery
42" × 42"	1067 × 1067 mm	Square 42	Drums, paint, telecom
48" × 48"	1219 × 1219 mm	Drum pallet	55-gallon drums
40" × 48"	1016 × 1219 mm	Rotated GMA	Military, construction
48" × 42"	1219 × 1067 mm	Chemical / produce	Chemicals, produce
40" × 40"	1016 × 1016 mm	Dairy square	Dairy, beverage
36" × 36"	914 × 914 mm	Beverage	DSD, retail display
48" × 20"	1219 × 508 mm	Retail half	Aisle-end displays
1200 × 800 mm	47.2" × 31.5"	EUR / EPAL 1	European export
1200 × 1000 mm	47.2" × 39.4"	ISO / EPAL 2	ISO export lanes

Per-layer fit

Interior widths vary by trailer build; confirm with your carrier before committing to a pattern.
Equipment	Interior width	Pattern	Per layer
53 ft dry van	100–102"	48×40 straight	26 pallets
53 ft dry van	100–102"	48×40 pinwheel	28 pallets
48 ft dry van	98–100"	48×40 straight	24 pallets
20 ft container	92.5"	1200×800 EUR	11 pallets
40 ft container	92.5"	1200×800 EUR	24 pallets
40 ft HC container	92.5"	1200×1000 ISO	20 pallets

Carbon model constants

Sources: industry LCA literature plus our own weighbridge and fuel records. Substitute your own figures — the Carbon Ledger shows the arithmetic.
Factor	Value	Basis
New hardwood pallet, embodied	12.6 kg CO₂e	Cradle-to-gate, regional oak
Recycled deck, processed	1.0 kg CO₂e	Repair, handling, yard energy
Net credit per reuse cycle	11.6 kg CO₂e	Difference of the two above
Heat treatment, per deck	0.9 kg CO₂e	Our chamber, measured
Average pallet mass	15 kg / 33 lb	12-month weighted mean
Road freight	0.11 kg CO₂e / ton-mile	Own fleet fuel records
Landfill volume, broken deck	0.12 yd³	Uncompacted, measured
Mature tree sequestration	21.8 kg CO₂e / yr	Illustration only
Break-even haul distance	≈ 950 miles	Beyond this, reuse credit is cancelled

Run the numbers on your own volumes →

ISPM-15 heat treatment

Core temperature: 56 °C minimum
Hold time: 30 continuous minutes
Probe points: Three per batch, deepest board
Batch capacity: ≈ 420 pallets
Mark elements: IPPC symbol, country, facility, HT
Marks required on: Two opposite sides, legible
Bark: Prohibited on every component
Records retained: 24 months
Invalidated by: Repair with untreated wood
Dunnage & bracing: In scope — must also be treated

Batch logs retained 24 months. A treated pallet repaired with untreated wood must be re-treated and re-marked.

Service rings from Meeks Blvd

Beyond roughly 950 miles, freight emissions cancel the carbon benefit of reuse. We will say so and recommend a nearer yard.
Ring	Distance	Example markets	Delivery window	Pickup window
One	0–60 mi	St. Louis, St. Charles, Metro East	Next business day	48 business hours
Two	60–180 mi	Columbia, Springfield IL, Cape Girardeau	2–4 business days	Within the week
Three	180–300 mi	Kansas City, Memphis, Indianapolis	Weekly scheduled run	By arrangement
Beyond	300+ mi	Quoted case by case	By arrangement	Full trailers only

Species in our intake, and how they behave

Densities and Janka figures are published wood-science values; the behaviour column is sixteen years of our own grading notes. Our intake is oak-dominant mixed hardwood.
Species	Group	Density (lb/ft³)	Janka hardness	Behaviour in a pallet
White oak	Hardwood	47	1,350 lbf	Our backbone: holds fasteners superbly, heavy, very durable
Red oak	Hardwood	44	1,290 lbf	Slightly more porous than white; excellent deck boards
Hickory	Hardwood	51	1,820 lbf	Hardest of our intake; superb stringers, splits if nailed dry
Maple	Hardwood	44	1,450 lbf	Clean, pale, dimensionally stable; good for upcycled tops
Ash	Hardwood	41	1,320 lbf	Tough and flexible; forgiving under impact
Poplar	Hardwood	29	540 lbf	Light hardwood, weaker fastener grip, fine for one-way
Southern yellow pine	Softwood	35	690 lbf	Common in new softwood builds; resinous, holds nails well
Spruce / fir	Softwood	27	510 lbf	Lightest option; loosens soonest under repeated handling

Moisture targets by application

Dryness is the single biggest determinant of recycled pallet quality — more than grade, species or board count.
Application	Target moisture	Why
Food distribution	≤ 19%	Mould risk, not strength; covered storage mandatory
Pharmaceutical / clean areas	≤ 15%	Documented dryness, often new material
General warehouse and racking	≤ 19%	Fastener grip and creep resistance
Cold chain	≤ 15% at dispatch	Condensation cycling through the dew point
Export, heat-treated	≤ 19%	Post-chamber typical; bark-free is the hard rule
Upcycled furniture stock	8–12%	Conditioned indoors two weeks before machining
Field and agricultural use	No target	Weather governs; buy #2 and expect it

Fasteners — two percent of the cost, most of the service life

Specify the fastener and the count per board-stringer intersection, not just the board count.
Fastener	Length	Shank	Withdrawal resistance	Where we use it
Helical-thread nail	2½"	Twisted, thread-cutting	High, survives moisture cycling	Standard on every new build and repair
Annular-ring nail	2¼"–2½"	Barbed rings	Highest	Lead boards and heavy racked specifications
Smooth-shank nail	2"–2½"	Plain	Low, drops as wood dries	Not used — the reason old pallets loosen
Screw-shank nail	2½"	Coarse helix	High	Block pallets and thick stringers
Staple	1¾"	Crown wire	Low in hardwood	Not used here; acceptable in softwood one-way pallets

Standards that actually govern a pallet

Only ISPM-15 is legally mandatory, and only for export. Everything else is a specification you can choose to be held to.
Standard	Issued by	Covers	Why it matters to you
ISPM-15	IPPC / FAO	Phytosanitary treatment of wood packaging	Mandatory for export; 56 °C core for 30 minutes, marked
ISO 6780	ISO	Principal pallet footprints	Defines the six international sizes, including 1200×800
ISO 8611	ISO	Pallet test methods and performance	The basis of static, dynamic and racked load figures
ASTM D1185	ASTM	Test methods for pallets and skids	North American equivalent test battery
GMA specification	Grocery Manufacturers Assoc.	48×40 four-way notched stringer pallet	What 'GMA' means when stated properly
EPAL / UIC 435	EPAL	Licensed European block pallet	Exchange-pool eligibility, marks and licensed repair
MH1	ANSI / MHI	Pallet terminology and dimensions	The vocabulary used on our build sheets
NWPCA uniform standard	NWPCA	Recycled pallet grading practice	The nearest thing the recycled market has to a rulebook

Handling and rack dimensions

Measure your own equipment before specifying a pallet. These are the values that decide whether a footprint works in your building.
Dimension	Typical value	Note
Fork length	42"–48"	Must not protrude beyond the far side of a 48" pallet
Fork width	4"–6"	Wider forks spread load across deck boards
Fork thickness	1½"–2"	Determines minimum pallet entry height
Fork spread, GMA entry	24"–27" centres	Between the stringers of a three-stringer pallet
Pallet-jack wheel path	6½" clear	Why notched stringers do not admit jacks
Minimum entry height	3½"	A crushed bottom deck blocks the forks entirely
Rack beam span, two pallets	≥ 96" clear	For two 48×40 pallets, 40" face out
Flue space, back to back	≥ 6"	Most fire codes; check your jurisdiction

The life of one deck, stage by stage

Durations are medians from our line records and the Passport programme; the population is survivor-biased and we say so.
Stage	Typical duration	What happens	Carbon position
Timber to pallet	Weeks	Sawn, nailed, often shipped wet	12.6 kg CO₂e embodied
First life	2–4 years	Hardest service; lead board usually fails	Credit begins at reuse
First repair	2 minutes	Lead board replaced with salvaged stock	+1.8 further lives on average
Second to fifth life	6–12 years	Grading, companions, re-nailing, re-grading	11.6 kg CO₂e avoided per cycle
Structural retirement	—	Stringers rotted or deck beyond rebuild	Stored carbon still retained
Repurposed	Decades	Collars, crates, table tops, cladding	Carbon stays in the material
Fiber	1–3 years	Mulch or bedding, then soil	Released slowly
Thermal	Immediate	Boiler-grade chip	Released at once — last resort

Total cost of a pallet programme, indexed

Index 100 = reactive spot buying. Observed across our managed accounts; your mix will differ, and we will model it against your own invoices for free.
Cost line	Spot buying	Managed programme	Comment
Pallet purchase price	Index 100	78–86	Grade matched to the job, not to panic
Emergency purchases	6–11% of spend	≈ 0%	Reserved stock removes the Friday scramble
Disposal and haulage	Index 100	0–20	Cores are bought, not binned
Internal labour on wood	Index 100	45–60	Sorting at source, scheduled collection
Product damage from pallets	Index 100	60–80	Fewer failures from under-specified decks
Admin and reconciliation	Index 100	30	One netted invoice a month
Reporting effort	Index 100	10	Diversion and CO₂e arrive automatically
Net first-year change	—	−18% to −34%	Observed across our managed accounts

End-of-line fiber products

Two percent of intake, screened rather than dumped.
Fiber product	Screen size	Made from	Sold to
Landscape mulch, coarse	1"–2"	Ground hardwood pallet stock	Landscapers, garden centres
Landscape mulch, fine	⅜"–1"	Screened second pass	Retail bagging, municipal beds
Animal bedding	⅛"–⅜"	Fine screen, metal-free	Livestock and poultry operations
Boiler-grade chip	Mixed	Material failing every screen above	Industrial thermal users
Recovered steel	n/a	Magnetically separated fasteners	Local scrap processor

Conversions we use daily

Inches to millimetres is exact. Rounding 1219 mm to 1200 mm is how container plans fail.
From	To	Multiply by
Inches	Millimetres	25.4 exactly
Pounds	Kilograms	0.4536
Short tons	Metric tonnes	0.9072
Cubic yards	Cubic metres	0.7646
Ton-miles	Tonne-kilometres	1.4594
°F to °C	—	(°F − 32) × 5⁄9
Board feet	Cubic metres	0.00236
lb/ft³	kg/m³	16.018

The thirteen named defects on our grading wall

01Cracked stringer through a nail line
02Stringer break longer than one board width
03Soft rot or fungal staining
04Missing deck board
05Split lead board
06Plug or scab repair
07Protruding or missing fastener
08Board thinner than specification
09Mixed board widths on one deck
10Pallet will not sit flat on a jig
11Visible chemical residue or paint
12Moisture above threshold
13Bark present on any component

A pallet is only downgraded for a defect a grader can name out loud. If it is not on this list, it is not a reason to move a pallet between lanes.

Glossary — thirty terms worth knowing

Core: A used pallet bought for grading — the currency of the industry.
Deck board: Any board on the top or bottom face of a pallet.
Lead board: The outermost deck board at each end; absorbs every fork entry.
Stringer: The long member running the length of a stringer pallet; usually three.
Stringer board: On a block pallet, the board that ties the blocks together.
Block: One of the nine supports in a block pallet.
Notch: The cut-out in a stringer that creates four-way fork access.
Chamfer: A bevel on a lead board's lower edge to ease fork entry.
Companion: A full-length board nailed alongside a damaged stringer. A strong repair.
Plug / scab: A short piece fixed over a break. A weaker repair; #2 grade here.
Re-nail: Restoring the fastener pattern on a loose but intact pallet.
Regrade: Moving a pallet between grade lanes after inspection.
Down-cut: Re-cutting a larger deck into a smaller footprint.
Static load: Capacity at rest on a flat, continuous surface.
Dynamic load: Capacity while being lifted and moved.
Racked load: Capacity spanning beams with no deck support. Always the smallest figure.
Unit load: Pallet, product and wrap considered as one structure.
Overhang: Load or deck projecting beyond its support. The leading cause of rack failure.
Flue space: The gap between back-to-back rack bays; six inches minimum in most codes.
GMA: The Grocery Manufacturers Association 48×40 specification.
EPAL: The licensing body for the European 1200×800 block pallet.
ISPM-15: The international phytosanitary standard for wood packaging.
HT: Heat treatment: 56 °C at core for 30 minutes.
IPPC mark: The wheat-sheaf stamp evidencing phytosanitary treatment.
Collar: Four hinged timber sides that turn a pallet into a container.
Top cap: A lightweight cover protecting the uppermost layer of a stack.
Dunnage: Timber used to fill voids, brace loads and spread point loads.
Fiber: Ground wood: mulch, animal bedding or boiler-grade chip.
Diversion rate: Share of intake kept out of landfill. Ours is 100%.
Reuse rate: Share of intake that leaves as a pallet. Ours is 94%.

Still wondering?

Eight questions that arrive most weeks. The full set lives on the FAQ page, and anything missing can go straight into the form at the top of this page.

Ask the yard

Asked most weeks

What is your minimum order?

100 pallets for metro delivery, 50 for a pickup of material you are selling us, a full trailer for out-of-region freight, and no minimum at all if you collect from the yard.

How quickly can you deliver?

Recycled stock in standard grades is usually same or next business day inside the metro. New builds run 3–7 business days; heat-treated 2–5.

Do you pay for used pallets?

Yes, for sound cores and most odd sizes. Genuinely scrap or contaminated wood carries a removal fee instead, and the offer always separates the two.

Can recycled pallets be used for export?

Only with a valid ISPM-15 heat-treatment mark. We re-treat and re-stamp recycled decks in our own registered chamber wherever the regulation allows it.

Are pallet grades standardised?

No. There is no enforced national standard, which is why we publish thirteen named defects and put the grade definition in writing before any contract.

Why is there no phone number?

The yard is loud and pallet enquiries are specific — counts, sizes, grades, postal codes. Written requests get accurate answers, usually the same business day.

Do you serve my area?

Routinely within 300 miles of St. Louis. Past roughly 950 miles the freight cancels the carbon benefit of reuse, and we will say so rather than quote it.

What happens if a load disappoints?

Tell us the same day. We re-grade, replace or credit, and we examine the lane that produced it. Grade disputes are information, not arguments.

Next step

The yard is open and the kettle is on

Visitors are welcome during business hours. Watch a stack get graded and argue with a grader in person.

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