How do you calculate furnace pull rate?

Divide actual furnace pull by planned furnace pull and multiply by 100. With 455 tons actual against 475 tons planned, that is 455 / 475 x 100 = 95.79%.

What is a good furnace pull performance for a glass container plant?

Most container furnaces target 97-99% of planned pull on a steady campaign. The example here at 95.79% sits 2.21 points under a 98% target, which is enough to warrant a downtime and gob-weight review.

Why is my furnace pulling below plan?

Common causes are forming-machine downtime starving the forehearths, gob weight running heavy, a throat or refractory restriction, or a quality hold that intentionally reduces pull. Pull rate flags the shortfall; downtime and reject logs explain it.

What is the difference between pull rate and melting rate?

Melting rate (often tons per square metre of melter per day) describes furnace design capacity, while pull rate measures actual delivered tonnage against your plan. You can hit melting capacity and still miss pull plan if forming downstream is down.

Can you over-pull a glass furnace?

Yes. Pushing pull above design shortens glass residence time, raises seed and stone defects, and accelerates refractory and superstructure wear, so a pull rate over 100% should be reviewed against quality data, not celebrated.

How does pull rate relate to specific energy consumption?

Furnaces are most thermally efficient near their design pull. Running well below plan, like the 95.79% example, raises energy per ton because the furnace still loses roughly the same heat while melting less glass.

Glass Container & Bottle Manufacturing calculator

Furnace pull rate Calculator

Furnace pull rate measures how much molten glass a container furnace actually delivers to the forming lines against what was planned, expressed as a percentage of the daily or weekly pull tonnage. Glass plant managers, batch and furnace engineers, and production schedulers watch this number daily because the furnace is the single most capital-intensive asset on site and runs continuously for 10-15 years between rebuilds. A pull rate that drifts below plan signals melting bottlenecks, gob weight drift, machine downtime starving the forehearths, or refractory wear that limits safe throughput. Tracking pull against a target also protects glass quality, because over-pulling a furnace shortens residence time and produces seeds, stones, and cord.

What this calculator does

Calculate furnace pull performance for glass bottle, jar, and container production by comparing actual packed glass tons to the planned furnace pull for the same period.
Use it when the furnace operator, batch house, or plant manager needs to see whether melt pull is supporting demand without over-pulling the furnace, starving the IS machines, or creating excess glass loss.
It computes furnace pull performance as actual tons pulled divided by planned tons, then the gap in percentage points between that performance and your target.

Formula used

Furnace pull performance = actual furnace pull ÷ planned furnace pull × 100
Furnace pull performance gap = furnace pull performance - target pull performance

Inputs explained

Actual furnace pull achieved:
Planned furnace pull target:
Target pull performance benchmark:

How to use the result

Use it at every shift handover and in daily production reviews to confirm the furnace is hitting its scheduled tonnage and to flag drift before it compounds.
Pull rate alone does not tell you why you missed plan; a 95.8% result could come from machine downtime, a forehearth restriction, or a deliberate quality hold, so always pair it with downtime and reject data.

Current U.S. benchmarks

Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate furnace pull rate? Divide actual furnace pull by planned furnace pull and multiply by 100. With 455 tons actual against 475 tons planned, that is 455 / 475 x 100 = 95.79%.
What is a good furnace pull performance for a glass container plant? Most container furnaces target 97-99% of planned pull on a steady campaign. The example here at 95.79% sits 2.21 points under a 98% target, which is enough to warrant a downtime and gob-weight review.
Why is my furnace pulling below plan? Common causes are forming-machine downtime starving the forehearths, gob weight running heavy, a throat or refractory restriction, or a quality hold that intentionally reduces pull. Pull rate flags the shortfall; downtime and reject logs explain it.
What is the difference between pull rate and melting rate? Melting rate (often tons per square metre of melter per day) describes furnace design capacity, while pull rate measures actual delivered tonnage against your plan. You can hit melting capacity and still miss pull plan if forming downstream is down.
Can you over-pull a glass furnace? Yes. Pushing pull above design shortens glass residence time, raises seed and stone defects, and accelerates refractory and superstructure wear, so a pull rate over 100% should be reviewed against quality data, not celebrated.

Last reviewed 2026-05-12.